Name: C7 Organic Chemistryvbio.weebly.com/uploads/2/8/2/4/2824362/c7_organic... · 2020-02-04 ·...

C7 Organic Chemistry35 Questions

Name: ________________________

Class: ________________________

Date: ________________________

Time:

Marks:

Comments:

of 115Brookvale Groby Learning Trust

The apparatus in the figure below is used to separate a mixture of liquids in a fuel.

(a) What is apparatus W on above the figure above?

Tick one box.

Beaker

Boiling Tube

Flask

Jug

(1)

1

(b) What is the name of this method of separation?

Tick one box.

Crystallisation

Electrolysis

Filtration

Distillation

(1)


(c) Name the changes of state taking place at A and B in the figure above.

Use words from the box.

boiling condensing freezing melting

Change of state at A: _________________________________________________

Change of state at B: _________________________________________________

(2)

(d) Table 1 shows the boiling points of the hydrocarbons in the fuel.

Table 1

HydrocarbonBoiling point

in °C

Pentane 36

Hexane 69

Heptane 98

Octane 125

Which hydrocarbon will be the last to collect in the beaker?

Tick one box.

Pentane

Hexane

Heptane

Octane

(1)


(e) The fuel is a mixture of liquids that has been designed as a useful product.

What name is given to this type of mixture?

Tick one box.

Catalyst

Formulation

Polymer

Solvent

(1)

(f) Describe how this fuel is different from crude oil.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(g) A student measured the melting point of a solid hydrocarbon four times.

The student’s results are in Table 2.

Table 2

Trial 1 Trial 2 Trial 3 Trial 4

Melting pointin °C

35 48 37 37

Calculate the mean melting point of the hydrocarbon, leaving out any anomalous result.

Give your answer to two significant figures.

___________________________________________________________________

___________________________________________________________________

Mean melting point = __________________ °C

(2)

(Total 10 marks)


A student investigated the substances produced when fuels burn.

The figure below shows the apparatus the student used.

(a) The complete combustion of a hydrocarbon produces carbon dioxide and one othersubstance.

Look at the figure above. What would the student see in tube A?

___________________________________________________________________

___________________________________________________________________

(1)

2

(b) When the student burned the fuel she saw soot in the funnel.

Explain why soot forms.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)


(c) The student burned another fuel which contained impurities.

The substance in tube B is water containing universal indicator.

The indicator turned red.

Which gas made the indicator turn red?

Tick one box.

Ammonia

Carbon monoxide

Nitrogen

Sulfur dioxide

(1)

(Total 4 marks)

(a) The hydrocarbon C16H34 can be cracked.

Balance the equation for cracking C16H34

C16H34 → ________________ C2H4 + C8H18

(1)

3

(b) Describe the differences between cracking and distillation.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)


(c) What type of reaction is cracking?

Tick one box.

Combustion

Decomposition

Neutralisation

Precipitation

(1)


(d) Ethene is used to make poly(ethene).

Poly(ethene) is used to make plastic bags.

the table below shows data from a Life Cycle Assessment (LCA) for a plastic bag and apaper bag.

Plastic bag Paper bag

Raw materials Crude oil or natural gas Wood

Energy used in MJ 1.5 1.7

Mass of solid waste in g 14 50

Mass of CO2 produced in kg 0.23 0.53

Volume of fresh water used in dm3 255 4 520

A company stated: ‘A Life Cycle Assessment shows that using plastic bags has lessenvironmental impact than using paper bags’.

Evaluate this statement. Use your knowledge and the information from above the tableabove.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(6)

(Total 10 marks)


There are several different forms of carbon and many different carbon compounds.

(a) Figure 1 shows a 3D model of a molecule of methane (CH4).

Figure 1

Draw the 2D structure of a methane molecule.

(1)

4

(b) Different forms of carbon have different bonding and structure.

Draw one line from the form of carbon to the bonding and structure.

Form of carbon Bonding and structure

(3)


(c) Crude oil is a mixture of many different carbon compounds.

Crude oil can be separated into useful fractions by fractional distillation.

Figure 2 shows a column used to separate crude oil.

Figure 2

Complete the sentences.

Use words from the box.

condense evaporate freeze

Crude oil is heated so that most of the compounds ____________________

At different temperatures the compounds cool and ____________________

(2)


(d) Which fraction is the most viscous?

Tick one box.

Engine oil

Diesel oil

Kerosene

Petrol

(1)

(e) Which fraction is the most flammable?

Tick one box.

Diesel oil

Kerosene

Petrol

Refinery gas

(1)

(f) Why does kerosene separate out of the mixture before diesel oil?

___________________________________________________________________

___________________________________________________________________

(1)

(Total 9 marks)


A student investigated the viscosity of liquid hydrocarbons.

A viscous liquid is a liquid that flows slowly.

The student used this method.

• Measure 50 cm 3 of the liquid hydrocarbon.

• Pour the liquid hydrocarbon into the funnel, as shown in Figure 1.

• Time how long it takes for all of the liquid hydrocarbon to run out of the funnel.

• Repeat the experiment for other liquid hydrocarbons.

(a) (i) Give the name of apparatus A in Figure 1.

______________________________________________________________

(1)

(ii) Name the apparatus that could be used to measure 50 cm3 of liquid hydrocarbon.

______________________________________________________________

(1)

5


(b) The student’s results for six liquid hydrocarbons are shown in Table 1.

Table 1

Formulaof liquidhydrocarbon

Time for liquid hydrocarbon to run out of thefunnel in seconds Mean time in

secondsExperiment 1 Experiment 2 Experiment 3

C5H12 12 11 13 12

C6H14 14 15 15 15

C7H16 19 20 18

C8H18 27 26 28 27

C10H22 46 48 47

C12H26 65 67 69 67


(i) The student did the experiment three times with each liquid hydrocarbon.

Give two reasons why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(ii) Use the data in Table 1 to calculate the mean time, in seconds, for C7H16

______________________________________________________________

______________________________________________________________

Mean time = __________________ seconds

(1)

(iii) Complete the sentence.

As the number of carbon atoms in a molecule of liquid hydrocarbon increases, thetime taken for the liquid hydrocarbon to run out of the funnel

________________________ .

(1)

(iv) A ring has been drawn around one result in Table 1.

This result has not been used to calculate the mean time for C10H22

Suggest why this result was not used.

______________________________________________________________

______________________________________________________________

(1)

(v) Suggest one error the student may have made to get the ringed result.

______________________________________________________________

______________________________________________________________

______________________________________________________________

(1)


(c) The student investigated the effect of temperature on the viscosity of one of the liquidhydrocarbons.

The liquid hydrocarbon he was using had the hazard symbols shown in Figure 2.

(i) Suggest why the student warmed the liquid hydrocarbon using warm water and not aBunsen flame.

______________________________________________________________

______________________________________________________________

(1)

(ii) The student wore safety glasses.

Give one other safety precaution the student should take, and give a reason for thissafety precaution.

Safety precaution _______________________________________________

Reason _______________________________________________________

______________________________________________________________

(2)

(d) This is the method the student used to investigate the effect of temperature on the viscosityof one of the liquid hydrocarbons.

• Measure 50 cm 3 of the liquid hydrocarbon and pour it into a beaker.

• Stand the beaker of liquid hydrocarbon in a heated water bath.

• Leave for a few minutes.

• Measure the temperature of the liquid hydrocarbon.

• Pour the liquid hydrocarbon into the funnel, as shown in Figure 3.


• Time how long it takes for all of the liquid hydrocarbon to run out of the funnel.

• Repeat the experiment at different temperatures.

(i) The student’s results are shown in Table 2.

Table 2

Temperature of liquidhydrocarbon in °C

Time to run out of thefunnel in seconds

23 27

30 21

37 17

46 16

55 11

65 9


Plot the results shown in Table 2 on the graph in Figure 4.

Draw a curve of best fit.

(3)

(ii) One of the points is anomalous.

Draw a ring around the anomalous point on your graph.

(1)

(iii) Predict how long it will take the liquid hydrocarbon to run through the funnel at 70 °C.

Show your working on your graph.

Time = ____________________ seconds

(2)

(iv) Describe the relationship between the temperature of the liquid hydrocarbon and theviscosity of the liquid hydrocarbon.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)

(v) The apparatus the student used in Figure 2 could lead to a systematic error in theresults.

Identify one source of systematic error, and describe how the student could avoid orreduce the error.

______________________________________________________________

______________________________________________________________


______________________________________________________________

______________________________________________________________

(2)

(Total 22 marks)

Methane (CH4) is used as a fuel.

(a) The displayed structure of methane is:

Draw a ring around a part of the displayed structure that represents a covalent bond.

(1)

6

(b) Why is methane a compound?

Tick ( ) one box.

Methane contains atoms of two elements, combined chemically.

Methane is not in the periodic table.

Methane is a mixture of two different elements.

(1)


(c) Methane burns in oxygen.

(i) The diagram below shows the energy level diagram for the complete combustion ofmethane.

Draw and label arrows on the diagram to show:

• the activation energy• the enthalpy change, ΔH.

(2)

(ii) Complete and balance the symbol equation for the complete combustion of methane.

CH4 + _____ CO2 + _____

(2)

(iii) Explain why the incomplete combustion of methane is dangerous.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(iv) Explain why, in terms of the energy involved in bond breaking and bond making, thecombustion of methane is exothermic.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)


(d) Methane reacts with chlorine in the presence of sunlight.

The equation for this reaction is:

Some bond dissociation energies are given in the table.

BondBond dissociation

energyin kJ per mole

C−H 413

C−Cl 327

Cl−Cl 243

H−Cl 432

(i) Show that the enthalpy change, ΔH, for this reaction is −103 kJ per mole.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(3)


(ii) Methane also reacts with bromine in the presence of sunlight.

This reaction is less exothermic than the reaction between methane and chlorine.

The enthalpy change, ΔH, is −45 kJ per mole.

What is a possible reason for this?

Tick ( ) one box.

CH3Br has a lower boiling point than CH3Cl

The C−Br bond is weaker than the C−Cl bond.

The H−Cl bond is weaker than the H−Br bond.

Chlorine is more reactive than bromine.

(1)

(Total 15 marks)

Crude oil is a fossil fuel.

(a) To make crude oil more useful it is separated into fractions.

Use the correct word from the box to complete each sentence.

boiling compound decomposition distillation

filtration mixture molecule

7

(i) Crude oil is a _________________________ of different substances.

(1)

(ii) The substances in crude oil have different

_________________________ points.

(1)

(iii) Crude oil is separated by fractional _________________________ .

(1)


(b) Petrol is one of the fractions produced from crude oil.

Car engines use a mixture of petrol and air.

The diagram shows some of the gases produced.

(i) What type of reaction happens to petrol in a car engine?

Tick ( ) one box.

combustion

decomposition

neutralisation

(1)

(ii) Petrol contains octane (C8H18).

Complete the word equation for the reaction of octane with oxygen.

octane + ______________ ______________ + ______________

(2)

(iii) Cars use sulfur-free petrol as a fuel.

Describe why sulfur should be removed from petrol.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)


(c) Some fractions from crude oil contain large hydrocarbon molecules.

These molecules can be cracked to produce smaller, more useful molecules.

An equation for cracking decane is:

C10H22 C3H8 + C2H4 + C5H10

decane propane ethene pentene

(i) Why is propane useful?

Tick ( ) one box.

Propane is a polymer.

Propane is an alloy.

Propane is a fuel.

(1)

(ii) Draw bonds to complete the displayed structure of ethene.

(1)

(iii) What is the colour change when bromine water reacts with ethene?

Tick ( ) one box.

Orange to colourless

Orange to green

Orange to red

(1)


(iv) Complete the sentence.

Pentene is useful because many pentene molecules can join together

to form _________________________ .

(1)

(Total 12 marks)

The diagram shows a carbon atom.

8

(a) (i) A proton is labelled.

Use the correct answer from the box to label each of the other sub-atomic particles.

electron ion molecule neutron

(2)

(ii) The atom of carbon is represented as:

What is the mass number of this carbon atom?

Draw a ring around the correct answer.

6 13 19

(1)

(iii) Complete the sentence.

Atoms of carbon have no overall electrical charge because the number

of protons is the same as the number of _______________________ .

(1)


(b) Butane is represented as:

(i) Use the correct answer from the box to complete each sentence.

bond compound helium hydrogen mixture oxygen

Butane is a ___________________ .

Butane contains atoms of carbon and ___________________ .

Each line between the atoms in butane represents a chemical

_________________ .

(3)

(ii) Which is the correct formula for butane?

Tick (✔) one box.

C4H4

C4H8

C4H10

(1)

(Total 8 marks)

The diagrams represent two compounds, A and B.

Compound A Compound B

(a) (i) Compound B is an alcohol.

Name compound B.

______________________________________________________________

(1)

9


(ii) Use the correct answer from the box to complete the sentence.

burned decomposed oxidised

To form compound A,

compound B is ___________________________________

(1)

(iii) Compounds A and B are both colourless liquids.

A test tube contains a colourless liquid, which could be either compound A orcompound B.

Describe a simple chemical test to show which compound, A or B, is in the test tube.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(b) Compounds A and B react to produce compound C and compound D.

Compound A Compound B Compound C

(i) What is the formula of compound D?

______________________________________________________________

(1)

(ii) Compound C is an ester.

Name compound C.

______________________________________________________________

(1)

(iii) State one use of esters.

______________________________________________________________

(1)

(Total 7 marks)


Sulfur is a non-metal.

Sulfur burns in the air to produce sulfur dioxide, SO2

(a) Why is it important that sulfur dioxide is not released into the atmosphere?

Tick (✔) one box.

Sulfur dioxide causes acid rain.

Sulfur dioxide causes global dimming.

Sulfur dioxide causes global warming.

(1)

10

(b) Sulfur dioxide dissolves in water.

What colour is universal indicator in a solution of sulfur dioxide?Give a reason for your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(c) Sulfur dioxide is a gas at room temperature.

The bonding in sulfur dioxide is covalent.

Explain, in terms of its structure and bonding, why sulfur dioxide has a low boiling point.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)


(d) In this question you will be assessed on using good English, organising information clearlyand using specialist terms where appropriate.

Sulfur dioxide is produced when fossil fuels are burned.

It is important that sulfur dioxide is not released into the atmosphere.

Three of the methods used to remove sulfur dioxide from gases produced when fossil fuelsare burned are:

• wet gas desulfurisation ( W)

• dry gas desulfurisation ( D)

• seawater gas desulfurisation ( S).

Information about the three methods is given in the bar chart and in Table 1 and Table 2.

Method of removing sulfur dioxide

Table 1

Method Material used How material is obtained

W Calcium carbonate, CaCO3 Quarrying

DCalcium oxide, CaO Thermal decomposition of calcium

carbonate:

CaCO3 CaO + CO2

S Seawater From the sea

Table 2

Method What is done with waste material

WSolid waste is sold for use in buildings.Carbon dioxide is released into the atmosphere.

D Solid waste is sent to landfill.

S Liquid waste is returned to the sea.


Evaluate the three methods of removing sulfur dioxide from waste gases.

Compare the three methods and give a justified conclusion.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(6)

(Total 12 marks)

Fossil fuels contain carbon and hydrogen.

(a) (i) Use the Chemistry Data Sheet to help you to answer this question.

Complete the figure below to show the electronic structure of a carbon atom.

(1)

11


(ii) Complete the word equation for the oxidation of hydrogen.

hydrogen + oxygen ______________________

(1)

(b) Coal is a fossil fuel.

Coal contains the elements hydrogen, sulfur, oxygen and carbon.

Name two products of burning coal that have an impact on the environment.

What impact does each of the products you named have on the environment?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)

(Total 6 marks)

This question is about oil reserves.

(a) Diesel is separated from crude oil by fractional distillation.

Describe the steps involved in the fractional distillation of crude oil.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

12


(b) Diesel is a mixture of lots of different alkanes.

What are alkanes?

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(c) In this question you will be assessed on using good English, organising information clearlyand using specialist terms where appropriate.

Petroleum products, such as petrol, are produced from crude oil.The graph shows the possible future production of petroleum products from crude oil andthe expected demand for petroleum products.


Canada’s oil sands hold about 20% of the world’s known crude oil reserves.

The oil sands contain between 10 to 15% of crude oil. This crude oil is mainly bitumen.

In Canada the oil sands are found in the ground underneath a very large area of forest. Thetrees are removed. Then large diggers and trucks remove 30 metres depth of soil and rockto reach the oil sands. The oil sands are quarried. Boiling water is mixed with the quarriedoil sands to separate the bitumen from the sand. Methane (natural gas) is burned to heatthe water.

The mixture can be separated because bitumen floats on water and the sand sinks to thebottom of the water. The bitumen is cracked and the products are separated by fractionaldistillation.

Use the information given and your knowledge and understanding to suggest theadvantages and disadvantages of extracting petroleum products from oil sands.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(6)

(Total 11 marks)


Energy is released by burning fuels.

(a) The bar chart shows the energy in kilojoules, kJ, released by burning 1 g of five differentfuels.

(i) Which fuel releases least energy by burning 1 g?

______________________________________________________________

(1)

13

(ii) How much energy is released by burning 1 g of coal?

Energy = _________________________kJ

(1)

(iii) Calculate the mass of petrol that will release the same amount of energy as 1 g ofhydrogen.

Use information from the bar chart to help you.

______________________________________________________________

______________________________________________________________

Mass = __________________ g

(1)


(b) Coal burns in oxygen and produces the gases shown in the table.

Name Formula

Carbon dioxide CO2

Water vapour H2O

Sulfur dioxide SO2

Use information from the table to name one element that is in coal.

___________________________________________________________________

(1)

(c) Hydrogen can be made from fossil fuels.Hydrogen burns rapidly in oxygen to produce water only.

A lighthouse uses electricity generated by burning hydrogen.

Suggest two advantages of using hydrogen as a fuel.

Use information from the bar chart and the diagram above to help you.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________

(2)

(Total 6 marks)


Scientists study the atmosphere on planets and moons in the Solar System to understand howthe Earth’s atmosphere has changed.

(a) Millions of years ago the Earth’s atmosphere was probably just like that of Mars today.

The table shows data about the atmosphere of Mars and Earth today.

Mars today Earth today

nitrogen 3% nitrogen 78%

oxygen trace oxygen 21%

water trace water trace

Carbon dioxide 95% Carbon dioxide trace

Average surface temperature −23°C Average surface temperature 15°C

The percentages of some gases in the Earth’s atmosphere of millions of years ago havechanged to the percentages in the Earth’s atmosphere today.

For two of these gases describe how the percentages have changed and suggest whatcaused this change.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

14


(b) Titan is the largest moon of the planet Saturn.Titan has an atmosphere that contains mainly nitrogen.Methane is the other main gas.

Main gases inTitan's atmosphere

Percentage (%)Boiling point in

°C

Nitrogen 95 −196

Methane 5 −164

Average surface temperature −178°C

When it rains on Titan, it rains methane!

Use the information above and your knowledge and understanding to explain why.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(c) Ultraviolet radiation from the Sun produces simple alkenes, such as ethene (C2H4) andpropene (C3H6) from methane in Titan’s atmosphere.

State the general formula for alkenes.

___________________________________________________________________

(1)

(Total 5 marks)

Alkanes are hydrocarbons found in crude oil.

(a) (i) Complete the sentence.

Hydrocarbons contain the elements _____________ and _____________only.

(1)

15


(ii) Ethane is an alkane with the formula C2H6

Draw a ring around the correct answer to complete the sentence.

Alkanes are hydrocarbons with the general formula

CnHn

CnH2n

CnH2n+2

(1)

(b) Crude oil is separated into useful fractions by fractional distillation.

Describe and explain how crude oil is separated into fractions by fractional distillation.

Use the diagram to help you answer the question.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)

(c) Dodecane (C12H26) from crude oil is cracked to produce ethene (C2H4).

(i) Complete the equation for this reaction.

C12H26 2 C2H4 + ______________

(1)


(ii) Give two conditions needed for cracking.

1. ____________________________________________________________

2. ____________________________________________________________

(2)

(Total 9 marks)

Saturated hydrocarbons, for example methane and octane, are often used as fuels.

(a) Methane can be represented as:

(i) The formula of methane is _________________________________ .

(1)

16

(ii) Draw a ring around the correct answer to complete the sentence.

In a saturated hydrocarbon molecule all of the bonds are

double.

ionic.

single.

(1)

(iii) Draw a ring around the correct answer to complete the sentence.

The homologous series that contains methane and octane is called the

alcohols.

alkanes.

alkenes.

(1)

(b) (i) The complete combustion of petrol produces carbon dioxide, water vapour and sulfurdioxide.

Name three elements petrol must contain.

1. ____________________________________________________________

2. ____________________________________________________________

3. ____________________________________________________________

(3)

(ii) The exhaust gases from cars can contain oxides of nitrogen.

Complete the sentence.

Nitrogen in the oxides of nitrogen comes from __________________ .

(1)


(iii) The sulfur dioxide and oxides of nitrogen from cars cause an environmental problem.

Name the problem and describe one effect of the problem.

Name of problem _______________________________________________

Effect of problem _______________________________________________

______________________________________________________________

(2)

(c) When a fuel burns without enough oxygen, there is incomplete combustion.

One gaseous product of incomplete combustion is carbon monoxide.

Name one solid product of incomplete combustion.

________________________________________

(1)

(d) A student investigated how well different hydrocarbon fuels would heat up 100 g of water.

Her hypothesis was:

The more carbon atoms there are in a molecule of any fuel, the better the fuel is.

The apparatus the student used is shown in the diagram.


She burned each hydrocarbon fuel for 2 minutes.

Her results are shown in the table.

Name ofhydrocarbon

fuel

Number ofcarbon atoms in

a molecule ofhydrocarbon

fuel

Temperaturechange ofwater in °C

after 2 minutes

Temperaturechange per gof fuel burned

Observations

Pentane 5 30 60 no smoke

Hexane 6 40 57 very small amount of smoke

Octane 8 55 55 small amount of smoke

Decane 10 57 52 large amount of smoke

Dodecane 12 60 43 very large amount of smoke

The student investigated only hydrocarbons.

Look carefully at her results.

How well do the student’s results support her hypothesis?

The more carbon atoms there are in a molecule of any fuel, the better the fuel is.

Give reasons for your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)


(e) A 0.050 mol sample of a hydrocarbon was burned in excess oxygen.

The products were 3.60 g of water and 6.60 g of carbon dioxide.

(i) Calculate the number of moles of carbon dioxide produced.

Relative atomic masses: C = 12; O = 16.

______________________________________________________________

______________________________________________________________

Moles of carbon dioxide = ___________________

(2)

(ii) When the hydrocarbon was burned 0.20 mol of water were produced.

How many moles of hydrogen atoms are there in 0.20 mol of water?

______________________________________________________________

Moles of hydrogen atoms = __________________

(1)

(iii) The amount of hydrocarbon burned was 0.050 mol.

Use this information and your answers to parts (e) (i) and (e) (ii) to calculate themolecular formula of the hydrocarbon.

If you could not answer parts (e) (i) or (e) (ii) use the values of 0.20 moles carbondioxide and 0.50 moles hydrogen. These are not the answers to parts (e) (i) and (e)(ii).

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

Formula = ________________________________

(2)

(Total 19 marks)


Barbecues are heated by burning charcoal or burning hydrocarbons.

(a) Use the Chemistry Data Sheet to help you to answer this question.

The chemical equation for charcoal burning is:

C + O2 CO2

Complete the word equation for this reaction.

carbon + __________________ carbon dioxide

(1)

17

(b) Propane is a hydrocarbon.

(i) Complete the displayed structure of propane. Draw in the missing bonds.

(1)

(ii) Write the chemical formula of propane. _________________________

(1)


(iii) Draw a ring around the correct answer to complete the sentence.

hydrogen.

Propane burns in air to produce carbon dioxide and hydroxide.

water.

(1)

(c) The table shows information about six hydrocarbons.

HydrocarbonState at room

temperature (20°C)Boiling point in °C

Ethane (C2H6) gas −89

Ethene (C2H4) gas −104

Butane (C4H10) gas −1

Butene (C4H8) gas −6

Hexane (C6H14) liquid +69

Hexene (C6H12) liquid +64

Tick ( ) two correct statements about the six hydrocarbons.

Statement Tick ( )

Ethane and butane boil at temperatures less than 20°C.

Hexene and butene are alkanes.

Butane and hexane are liquid at 0°C.

Ethene and hexene each have a carbon-carbon double bond.

(2)

(Total 6 marks)

Crude oil is a mixture of many different chemical compounds.

(a) Fuels, such as petrol (gasoline), can be produced from crude oil.

(i) Fuels react with oxygen to release energy.

Name the type of reaction that releases energy from a fuel.

______________________________________________________________

(1)

18


(ii) Fuels react with oxygen to produce carbon dioxide.The reaction of a fuel with oxygen can produce a different oxide of carbon.

Name this different oxide of carbon and explain why it is produced.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(b) Most of the compounds in crude oil are hydrocarbons.Hydrocarbons with the smallest molecules are very volatile.

In this question you will be assessed on using good English, organising information clearlyand using specialist terms where appropriate.

Describe and explain how petrol is separated from the mixture of hydrocarbons in crudeoil.


Use the diagram and your knowledge to answer this question.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(6)

(Total 9 marks)

(a) Crude oil is a mixture of compounds.These compounds are made up of hydrogen and carbon atoms only.

(i) Draw a ring around the correct answer to complete the sentence.

alcohols.

Compounds made up of carbon andhydrogen atoms only are called

hydrocarbons.

vegetable oils.

(1)

19

(ii) The table shows five of these compounds.

CompoundState at room

temperature (20 °C)Boiling point in °C

ethane, C2H6 gas – 89

butane, C4H10 gas 0

hexane, C6H14 liquid +69

pentadecane, C15H32 liquid +270

heptadecane, C17H36 solid +302


Tick ( ) two correct statements about the five compounds.

Statement Tick ( )

ethane has the smallest molecules

hexane and pentadecane are liquid at 100 °C

heptadecane has the highest boiling point

butane boils at 100 °C

(2)

(iii) Draw a ring around the correct answer to complete each sentence.

Fractional distillation is used to separate the compounds in crude oil.

cracking

The first step in fractional distillation is displacing the crude oil.

evaporating

burn

During fractional distillation the compounds condense at differenttemperatures.

decompose

(2)


(b) Steam distillation is used to separate oils from plants.

The diagram shows some apparatus that can be used to separate oil from lavender plants.Four parts of the apparatus are labelled W, X, Y and Z.

(i) In which part, W, X, Y or Z, of the apparatus:

is steam produced

are steam and oil condensed?

(2)

(ii) Use the correct word from the box to complete the sentence.

dissolves floats sinks

When the oil separates from the water, the oil ___________________

(1)

(iii) Describe how part Z of the apparatus can be used to remove the water from the oil.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 10 marks)


A mixture of petrol and air is burned in a car engine.Petrol is a mixture of alkanes. Air is a mixture of gases.

The tables give information about the composition of petrol and the composition of air.

Petrol Air

Alkane Formula Gas Percentage (%)

hexane C6H14 nitrogen 78

heptane oxygen 21

octane C8H18 carbon dioxide 0.035

nonane C9H20 Small amounts of other gases and watervapour

decane C10H22

(a) Use the information above to answer these questions.

(i) Give the formula for heptane

______________________________________________________________

(1)

20

(ii) Complete the general formula of alkanes.n = number of carbon atoms

CnH(1)

(b) Alkanes in petrol burn in air.The equations represent two reactions of hexane burning in air.

Reaction 1 2C6H14 + 19O2 → 12CO2 + 14H2O

Reaction 2 2C6H14 + 13O2 → 12CO + 14H2O

Reaction 2 produces a different carbon compound to Reaction 1.

(i) Name the carbon compound produced in Reaction 2.

______________________________________________________________

(1)

(ii) Give a reason why the carbon compounds produced are different.

______________________________________________________________

______________________________________________________________

(1)


(c) The table shows the percentages of some gases in the exhaust from a petrol engine.

Name of gas Percentage (%)

nitrogen 68

carbon dioxide 15

carbon monoxide 1.0

oxygen 0.75

nitrogen oxides 0.24

hydrocarbons 0.005

sulfur dioxide 0.005

other gases

(i) What is the percentage of the other gases in the table?

______________________________________________________________

(1)

(ii) What is the name of the compound that makes up most of the other gases?

______________________________________________________________

(1)

(iii) Give a reason why sulfur dioxide is produced in a petrol engine.

______________________________________________________________

______________________________________________________________

(1)

(iv) State how nitrogen oxides are produced in a petrol engine.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)


(d) Many scientists are concerned about the carbon dioxide released from burning fossil fuelssuch as petrol.

Explain why.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 11 marks)


About 3000 million years ago carbon dioxide was one of the main gases in the Earth’s earlyatmosphere.

About 400 million years agoplants and trees grew on mostof the land. When the plantsand trees died they werecovered by sand and slowlydecayed to form coal.

Today coal is burned in powerstations to release the energyneeded by industry.

(a) The bar chart shows the percentage of some of the elements in this coal.

(i) This coal contains 85 % carbon. Draw the bar for carbon on the chart.

(1)

21


(ii) Coal is burned in the atmosphere to release energy.Two of the products of burning coal are shown.

Draw one line from each product to its environmental impact.

Product Environmental impact

Acid rain

Sulfur dioxide

Global dimming

Carbon particles

Global warming

(2)

(b) Use the information above and your knowledge and understanding to answer thesequestions.

(i) How did the formation of coal decrease the amount of carbon dioxide in the Earth’searly atmosphere?

______________________________________________________________

______________________________________________________________

(1)

(ii) How does burning coal affect the amount of carbon dioxide in the Earth’satmosphere?Explain your answer.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 6 marks)


Petroleum diesel is a fuel made from crude oil.Biodiesel is a fuel made from vegetable oils.To make biodiesel, large areas of land are needed to grow crops from which the vegetable oilsare extracted.Large areas of forest are cleared by burning the trees to provide more land for growing thesecrops.

(a) Use this information and your knowledge and understanding to answer these questions.

(i) Carbon neutral means that there is no increase in the amount of carbon dioxide in theatmosphere.

Suggest why adverts claim that using biodiesel is carbon neutral.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

22


(ii) Explain why clearing large areas of forest has an environmental impact on theatmosphere.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(b) Why is there an increasing demand for biodiesel?

___________________________________________________________________

___________________________________________________________________

(1)

(c) Suggest why producing biodiesel from crops:

(i) causes ethical concerns

______________________________________________________________

______________________________________________________________

(1)

(ii) causes economic concerns.

______________________________________________________________

______________________________________________________________

(1)

(Total 7 marks)


About 3000 million years ago, carbon dioxide was one of the main gases in the Earth’satmosphere.

About 400 million years ago, plants and trees grew on most of the land. When the plants andtrees died they were covered by sand and slowly decayed to form coal.

(a) Describe and explain how the composition of the Earth’s atmosphere was changed by theformation of coal.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

23

(b) Today, coal is burned in power stations to release the energy needed by industry.Carbon dioxide, water and sulfur dioxide are produced when this coal is burned.

Name three elements that are in this coal.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(c) In some power stations coal is mixed with calcium carbonate (limestone).The mixture is crushed before it is burned.

(i) Many chemical reactions happen when this mixture is burned.The chemical equation represents one of these reactions.

Balance the chemical equation.

2CaCO3(s) + 2SO2(g) + O2(g) → … … …CaSO4(s)

+ … … …CO2(g)

(1)


(ii) Explain how the use of calcium carbonate in the mixture:

increases atmospheric pollution

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

decreases atmospheric pollution.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(4)

(Total 10 marks)

There are two main types of diesel fuel used for cars:

• biodiesel, made from vegetable oils

• petroleum diesel, made from crude oil.

(a) A scientist compared the viscosity of biodiesel with petroleum diesel at differenttemperatures.The scientist measured the time for the same volume of diesel to flow through a small holein a cup.The scientist’s results are plotted on the grid.

(i) Draw a line of best fit for the biodiesel results.

(1)

24


(ii) What conclusions can the scientist make about the viscosity of biodiesel comparedwith the viscosity of petroleum diesel at different temperatures?

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(iii) Biodiesel may be less suitable than petroleum diesel as a fuel for cars.Use these results to suggest one reason why.

______________________________________________________________

______________________________________________________________

(1)


(b) Biodiesel can be mixed with petroleum diesel to make a fuel for cars.In a car engine, the diesel fuel burns in air.The waste products leave the car engine through the car exhaust system.The bar chart compares the relative amounts of waste products made when three differenttypes of diesel fuel burn in a car engine.

Nitrogen oxides and sulfur dioxide cause a similar environmental impact.

(i) What environmental impact do particulates from car exhaust systems cause?

______________________________________________________________

(1)

(ii) What is the percentage reduction in particulates when using B100 instead ofpetroleum diesel?

_____________________ %

(1)


(iii) Replacing petroleum diesel with biodiesel increases one type of environmentalpollution.

Use the bar chart and the information given to explain why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(iv) A carbon neutral fuel does not add extra carbon dioxide to the atmosphere.

Is biodiesel a carbon neutral fuel?

Use the bar chart and your knowledge to explain your answer.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 10 marks)


Read the article and then answer the questions.

Supermarkets launch eco-friendly plastic milk bags.Could this be the end of the milk bottle?

Milk bottles are made from glass or from plastic.

Glass milk bottles contain 0.5 litres of milk. When the milk is used up the emptybottles are returned to be re-used. Glass milk bottles are re-used 24 times onaverage. The glass to make new milk bottles is produced when a mixture of sand,limestone, soda and recycled glass is heated to about 1600 °C in a furnace. Thereare almost unlimited amounts of the raw materials needed to produce this glass.About 35% of used glass is recycled.

The most common plastic milk bottles contain 2 litres of milk. When the milk isused up the empty bottles are discarded as waste. The plastic used to make thesemilk bottles is poly(ethene). Poly(ethene) is produced from crude oil by first usingfractional distillation, then cracking the naphtha fraction and finally polymerising theethene. About 5% of used poly(ethene) is recycled.

The new plastic milk bags contain 2 litres of milk. The milk bags are also madefrom poly(ethene). A milk bag uses 75% less poly(ethene) than is used to make thepoly(ethene) milk bottles. When the milk is used up the empty bags are discarded aswaste.

(a) Describe what happens in fractional distillation so that fractions, such as naphtha, areseparated from crude oil.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

25


(b) Supermarkets claim that using milk bags instead of milk bottles would have lessenvironmental impact.

Do you agree with this claim?

Use the information in the article and your knowledge and understanding to makeappropriate comparisons to justify your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)

(Total 7 marks)


Crude oil is used to produce many useful materials.

(a) The diagram shows some of the fractions produced from crude oil by fractional distillation.

Use the diagram to help you to explain how crude oil is separated into fractions.

You should use the words evaporated and condensed in your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

26


(b) The table shows some information about four of the fractions from crude oil that are usedas fuels.

Fraction Boiling point in °C Number of carbon atomsfound in the molecules

Gasoline (petrol) 20 - 200 5 - 10

Kerosene (paraffin) 180 - 260 10 - 16

Diesel 260 - 340 14 - 20

Fuel oil 370 - 600 20 - 70

Use the information in the table to help you to answer these questions.

(i) How can you tell that each of the fractions is a mixture?

______________________________________________________________

______________________________________________________________

(1)

(ii) How does the number of carbon atoms in a molecule affect its boiling point?

______________________________________________________________

______________________________________________________________

(1)

(c) Fuels are substances that release energy.

(i) Name the reaction that releases energy from a fuel such as gasoline (petrol).

______________________________________________________________

(1)

(ii) Describe how fuel oil is broken down into smaller, more useful molecules such asgasoline (petrol).

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 8 marks)


Supermarkets in the UK have been advised by the Government to stop giving plastic bags tocustomers. The Government states that this is because plastic bags use up resources that arenot renewable and that the manufacture of plastic bags produces carbon dioxide.Most of these plastic bags are made from poly(ethene). The table shows methods to deal withlarge numbers of used plastic bags.

Method Description of what happens to the plastic bag

Reused used again by the customer

Recycled collected, transported, washed and melted to make new plastic items

Burned collected, transported and burnt to release heat energy

Dumped mixed with other household waste, collected, transported anddisposed of at a landfill site

Use the information and your knowledge and understanding to briefly give one advantage andone disadvantage for each of these methods.

Reused ________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

Recycled _______________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

Burned ________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

Dumped _______________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

(4)

(Total 4 marks)

27


This information about diesel was printed in a magazine.

Almost all of the crops that we eat can be converted into fuel for cars.Vegetable oils can be used as biodiesel. Diesel from crude oil is called fossil diesel.When either biodiesel or fossil diesel burn they both produce similar amounts of carbon dioxide.Both types of diesel produce carbon monoxide. However, biodiesel produces fewer carbonparticles and less sulfur dioxide.

(a) Carbon monoxide can be produced when diesel burns in a car engine. Explain how.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

28

(b) Use the information at the start of this question and your knowledge and understanding toevaluate the use of biodiesel compared with fossil diesel as a fuel for cars.

Remember to give a conclusion to your evaluation.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(5)

(Total 7 marks)


In the future:

• there will be fewer oil burning power stations

• there may be more wood burning power stations.

(a) Which one of the emissions from the chimney can cause acid rain?

___________________________________________________________________

(1)

29

(b) Draw a ring around the correct answer to complete the sentence.

acid rain.

Carbon particles in the Earth’s atmosphere cause global dimming.

global warming.

(1)

(c) Which gas in the air is needed for oil or wood to burn?

___________________________________________________________________

(1)

(d) Suggest why there will be fewer power stations burning oil in the future.

___________________________________________________________________

___________________________________________________________________

(1)


(e) Some power stations burn wood.The wood comes from trees grown in forests.

Suggest why burning wood in power stations is said to be ‘carbon-neutral’.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 6 marks)

Crude oil is a mixture of hydrocarbons.Crude oil can be separated into fractions.

(a) (i) Complete the sentence.

The process used to separate the crude oil into fractions is called

fractional ______________________________ .

(1)

30

(ii) Why do the fractions separate at different temperatures?

______________________________________________________________

______________________________________________________________

(1)


(b) Tick ( ) two properties of fraction 6.

Property Tick ( )

contains hydrocarbons

has a small number of carbon atoms in each molecule

is easy to ignite

has a high boiling point

(2)

(c) Fraction 1 contains hydrocarbons called alkanes.The general formula of an alkane is: CnH2n+2

What is the formula of the alkane that has 5 carbon atoms in each molecule?

Draw a ring around the correct answer.

C5H9 C5H10 C5H11 C5H12

(1)

(Total 5 marks)

Crude oil is a mixture of hydrocarbons. Most of these hydrocarbons are alkanes.

(a) The general formula of an alkane is CnH2n+2

Complete the structural formula for the alkane that has six carbon atoms in its molecules.

(1)

31


(b) The boiling points of alkanes are linked to the number of carbon atoms in their molecules.

(i) Describe the link between the number of carbon atoms in an alkane molecule and itsboiling point.

______________________________________________________________

______________________________________________________________

(1)

(ii) Suggest two reasons why all of the alkanes in the bar chart are better fuels than thealkane with the formula C30H62

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)


(c) During the last 200 million years the carbon cycle has maintained the percentage of carbondioxide in the atmosphere at about 0.03 %.Over the last 100 years the percentage of carbon dioxide in the atmosphere has increasedto about 0.04 %.Most of this increase is caused by burning fossil fuels to heat buildings, to generateelectricity and to power our transport.Fossil fuels contain carbon that has been locked up for millions of years.

(i) Burning fossil fuels, such as petrol, releases this locked up carbon. Balance thechemical equation for the combustion of one of the alkanes in petrol.

2 C8H18 + 25 O2 ____ CO2 + ____ H2O

(1)

(ii) Where did the carbon that is locked up in fossil fuels come from?

______________________________________________________________

______________________________________________________________

(1)

(iii) The burning of fossil fuels has caused the percentage of carbon dioxide in theatmosphere to increase to above 0.03 %.Explain why.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 8 marks)


Petroleum diesel is produced from crude oil.

Most vehicles that use petroleum diesel as fuel can also use biodiesel or a mixture of these twofuels. In the UK (in 2010) there must be 5 % biodiesel in all petroleum diesel fuel.

Biodiesel is produced from plant oils such as soya. The crops used to produce biodiesel can alsobe used to feed humans. The benefit that biodiesel is ‘carbon neutral’ is outweighed by theincreasing demand for crops. This increasing demand is causing forests to be burnt to provideland for crops to produce biodiesel. Only a huge fall in the price of petroleum diesel would haltthe increasing use of biodiesel.

The graph shows the average percentage change in exhaust emissions from vehicles usingdifferent mixtures of petroleum diesel and biodiesel.

There is no difference in carbon dioxide emissions for all mixtures of petroleum diesel andbiodiesel.

Use the information and your knowledge and understanding to evaluate the use of plant oils toproduce biodiesel.

Remember to give a conclusion to your evaluation.

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

32


_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

(5)

(Total 5 marks)

Natural gas is mainly a hydrocarbon called methane.

(a) Use one word from the box to complete the sentence.

compounds elements molecules

Hydrocarbons contain hydrogen and carbon only.

Hydrogen and carbon are _____________________________________________ .

(1)

33

(b) The diagrams represent atoms of hydrogen and carbon.

Draw a ring around the correct answer to complete the sentences.

bond.

(i) The centre of each atom is called the nucleus.

symbol.

(1)


three

(ii) The hydrogen atom has one electron and the carbon atom has four electrons.

six

(1)

(c) A molecule of methane can be represented as

Draw a ring around the correct answer to complete the sentences.

CH

(i) The formula of methane is CH4

C4H4

(1)

bond.

(ii) The line between C—H is called a molecule.

nucleus.

(1)

(d) Methane burns to produce carbon dioxide (CO2) and water (H2O).

(i) Draw a ring around the correct answer to complete the sentence.

carbon.

When methane burns it reacts with nitrogen.

oxygen.

(1)

(ii) Hydrogen (H2) can be used as a fuel.

Suggest why burning hydrogen would be less harmful to the environment thanburning methane.

______________________________________________________________

______________________________________________________________

(1)

(Total 7 marks)


In the future more coal-fired and fewer oil-fired power stations will be used to generate electricity.When coal and oil are burned they produce the same types of emissions which can causeenvironmental problems.

(a) Emissions from the chimney can cause acid rain, global dimming and global warming.Draw one straight line from each possible environmental problem to the emission thatcauses it.

Possible environmental problem Emission that causes it

carbon particles

acid rain

carbon dioxide

global warming

sulfur dioxide

global dimming

water vapour

___________________________________________________________________

(3)

34

(b) Draw a ring around the correct word in the box to complete each sentence.

carbon dioxide.

(i) Incomplete combustion of coal or oil is caused by too little nitrogen.

oxygen.

(1)


carbon monoxide.

(ii) A gas formed by the incomplete combustion of coal or oil is hydrogen.

oxygen.

(1)

(c) The table shows the world production for both coal and oil in 2000.

The world production figures after 2000 are predicted.

Year World production of coal(billions of tonnes per year)

World production of oil(billions of barrels per year)

2000 3.5 12.5

2050 4.5 5.6

2100 5.0 1.7

2150 5.5 0.5

2200 6.0 0.0

(i) How is the world production of oil predicted to change from 2000 to 2200?

______________________________________________________________

______________________________________________________________

(1)

(ii) Suggest two reasons why the world production of coal is predicted to increase.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

______________________________________________________________

(2)

(Total 8 marks)


(a) Alkanes are important hydrocarbon fuels. They have the general formula CnH2n+2

The points on the graph show the amount of energy released when 1 mole of methane(CH4), ethane (C2H6), propane (C3H8) and butane (C4H10) are burned separately.

(i) Draw a line through the points and extend your line to the right-hand edge of thegraph.

(1)

35

(ii) Use the graph to estimate the amount of energy released when 1 mole of octane(C8H18) is burned.

Energy released = ____________________ kJ

(1)

(iii) Suggest why we can make a good estimate for the energy released by 1 mole ofpentane (C5H12).

______________________________________________________________

______________________________________________________________

(1)


(iv) A student noticed that octane (C8H18) has twice as many carbon atoms as butane(C4H10), and made the following prediction:

“When burned, 1 mole of octane releases twice as much energy as 1 mole ofbutane.”

Use the graph to decide if the student’s prediction is correct. You must show yourworking to gain credit.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(b) Some information about four fuels is given in the table.

Combustion products

Fuel Type Heat releasedin kJ per g

CO2 SO2 H2O Type of flame

Bio-ethanol Renewable 29 Not smoky

Coal Non-renewable 31 Smoky

Hydrogen Renewable 142 Not smoky

Natural gas Non-renewable 56 Not smoky

From this information a student made two conclusions.

For each conclusion, state if it is correct and explain your answer.

(i) “Renewable fuels release more heat per gram than non-renewable fuels.”

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)


(ii) “Non-renewable fuels are better for the environment than renewable fuels.”

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(Total 9 marks)


Mark schemes

(a) Flask11

(b) Fractional distillation1

(c) A – boiling

in this order1

B – condensing1

(d) Pentane1

(e) Formulation1

(f) the fuel is a pure compound1

and crude oil is a mixture

or

the fuel is made up of four hydrocarbons

allow crude oil contains a large number of compounds and the fuelcontains four

and crude oil could have many more1

(g) (35 + 37 + 37 / 3) = 36.331

361

allow (35 + 48 + 37 + 37 / 4 =) 39(.25) for 1 mark

[10]

(a) Colourless liquid / condensation / water12

(b) incomplete combustion of the fuel1

because not enough oxygen1

(c) Sulfur dioxide1

[4]

(a) 4 (C2H4)13


(b) cracking involves a catalyst1

distillation does not

or

distillation does not involve a chemical change

but cracking does1

(c) Decomposition1

(d) Level 3 (5–6 marks):A logically structured evaluation with links involving several comparisons. Nearly all pointsmade are relevant and correct.

Level 2 (3–4 marks):Some valid comparisons made between the two types of bag. There may be someincorrect or irrelevant points.

Level 1 (1–2 marks):A vague response with few correct and relevant points and with no direct comparisons.

0 marks:No relevant content

Indicative content

Accept converse in terms of plastic bags for all statements• Paper bags are made from a renewable resource• Plastic bags are made from a finite resource• Paper bags require more energy to manufacture• Paper bags produce more waste• Paper bags are biodegradable• Paper bags create more CO 2

• CO 2 created by paper bags offset by photosynthesis in growing wood• Paper bag requires much more fresh water• Paper bags cannot be recycled• Agree because non-renewability less important than other factors or disagree

because of converse or can’t say because data inconclusive / incomplete6

[10]

(a)

1

4


(b) Form of carbon Bonding and structure

extra lines from the left negate the mark3

(c) evaporate1

condense1

(d) Engine oil1

(e) Refinery gas1

(f) because its boiling point is lower1

[9]

(a) (i) (conical) flask1

(ii) measuring cylinder / pipette / burette1

5


(b) (i) any two from:• so anomalous results could be identified / ignored• so a mean / average could be taken• (to improve) accuracy

2

(ii) 191

(iii) increases / gets longer / gets bigger1

(iv) anomalous / does not agree with other times for C10H221

(v) any one from:• shorter hydrocarbon used• volume of hydrocarbon too small• started timing late• stopped timing too early / when liquid left in funnel

must suggest why the result is lower than the others.

allow the temperature was higher or the students used a widerfunnel.

1

(c) (i) flammable1

(ii) suitable safety precaution1

reason that links the safety precaution to the hazard symbols

eg:

• wear gloves

• (because) it is hazardous to health / harmful / toxic / irritant

or

• do not pour down sink or dispose of properly

• (because) it is harmful to the environment / kills fish

or

• wear a mask or do it in the fume cupboard or a well-ventilated area

• respiratory irritant1


(d) (i) points plotted correctly (within half small square)

all six points correct scores 2

3, 4 or 5 points correct scores 12

smooth curve of best fit1

(ii) point at 46 °C circled

allow point furthest from the line as drawn1

(iii) working shown on graph1

value read from graph line drawn (within half small square)1

(iv) the higher the temperature the lower the viscosity

allow the higher the temperature the lower / shorter the time takenfor 1 mark

2

non-linear or change gets smaller as temperature gets higher

answer relating temperature to time taken can score a maximum of2 marks.

1

(v) identifying source of the error1

method of avoiding the error

eg:

• the temperature will drop

• insulate the funnel

or

• runs out before all added

• put a tap on the funnel1

[22]

(a) circle round any one (or more) of the covalent bonds

any correct indication of the bond − the line between letters1

6

(b) Methane contains atoms of two elements, combined chemically1


(c) (i) activation energy labelled from level of reagents to highest point of curve

ignore arrowheads1

enthalpy change labelled from reagents to products

arrowhead must go from reagents to products only1

(ii) 2 O21

2 H2O

if not fully correct, award 1 mark for all formulae correct.

ignore state symbols1

(iii) carbon monoxide is made1

this combines with the blood / haemoglobin or prevents oxygen being carried inthe blood / round body or kills you or is toxic or poisonous

dependent on first marking point1

(iv) energy is taken in / required to break bonds

accept bond breaking is endothermic1

energy is given out when bonds are made

accept bond making is exothermic1

the energy given out is greater than the energy taken in

this mark only awarded if both of previous marks awarded1


(d) (i) energy to break bonds = 1895

calculation with no explanation max = 21

energy from making bonds = 19981

1895 − 1998 (= −103)orenergy to break bonds = 656energy from making bonds = 759656 − 759 (= −103)

allow:

bonds broken − bonds made =413 + 243 − 327 − 432 = -103 for 3 marks.

1

(ii) The C — Br bond is weaker than the C — Cl bond1

[15]

(a) (i) mixture (of different substances)1

(ii) boiling (points)1

(iii) distillation1

7

(b) (i) combustion1

(ii) (reactant)

oxygen

allow correct formulae1

(products)

products in any order

carbon dioxide

allow carbon or carbon monoxideandwater

allow water vapour or steam or hydrogen oxide1

(iii) (burning sulfur) produces sulfur dioxide / S02

allow it / sulfur reacts with oxygen ignore sulfur oxide1

causes acid rain1


(c) (i) propane is a fuel1

(ii) double bond drawn between carbon atoms

do not allow any other bonds or symbols1

(iii) orange to colourless1

(iv) poly(pentene)

allow polymer(s)1

[12]

(a) (i) Neutron (top label)18

Electron (bottom label)1

(ii) 131

(iii) electrons1

(b) (i) compound1

hydrogen1

bond1

(ii) C4H101

[8]

(a) (i) ethanol19

(ii) oxidised1

(iii) Test

add any named carbonate or hydrogen carbonate

the first mark is for the test; the second is for the result

if the test is incorrect award 0 marks.1

Result

A will effervesce (carbon dioxide) or B will not effervesce.

if the result is incorrect, award the first mark only1


or

candidates do not have to name a gas but penalise an incorrectgas.

Test

add a named (magnesium, aluminium, zinc, iron or tin) metal

give credit to any test that will work.

Result

A will effervesce (hydrogen), B will not

allow a test that would identify B.

or

Test

add an acid-base indicator

Result

credit any acid colour for that indicator eg for universal indicator allow red,yellow or orange

give credit for the neutral colour for B

or

Test

add an alcohol (+ acid catalyst)

Result

sweet or fruity smell of esters.

(b) (i) H2O1

(ii) ethyl ethanoate1

(iii) any one from:

• flavourings• perfumes• solvents• plasticisers

allow any correct use of esters1

[7]

(a) Sulfur dioxide causes acid rain.110


(b) red / orange / yellow

do not accept any other colours1

because sulfur dioxide (when in solution) is an acid1

(c) (there are) weak forces (of attraction)

do not accept any reference to covalent bonds breaking1

between the molecules

do not accept any other particles1

(these) take little energy to overcome

award third mark only if first mark given1


(d) Marks awarded for this answer will be determined by the Quality of Communication(QC) as well as the standard of the scientific response. Examiners should also referto the information on page 5 and apply a ‘best-fit’ approach to the marking.

0 marksNo relevant content

Level 1 (1 – 2 marks)A relevant comment is made about the data.

Level 2 (3 – 4 marks)Relevant comparisons have been made, and an attempt made at a conclusion.

Level 3 (5 – 6 marks)Relevant, detailed comparisons made and a justified conclusion given.

examples of the points made in the response

effectiveness

• W removes the most sulfur dioxide• D removes the least sulfur dioxide

material used

• Both W and D use calcium carbonate• Calcium carbonate is obtained by quarrying which will create scars on

landscape / destroy habitats• D requires thermal decomposition, this requires energy• D produces carbon dioxide which may cause global warming / climate change• S uses sea water, this is readily available / cheap

waste materials

• W product can be sold / is useful• W makes carbon dioxide which may cause global warming / climate change• D waste fill landfill sites• S returned to sea / may pollute sea / easy to dispose of

6

[12]

(a) (i) 2,4 drawn (as dots / crosses / e–)1

11

(ii) Water (vapour) / steam

allow hydrogen oxide / H2O

do not accept hydroxide1


(b) any two pairs from:

carbon dioxide (1)

causes global warming (1)

allow greenhouse effect / climate change / sea level rise / melting ofpolar ice caps

or

carbon (particles) / soot (1)

allow particulates

causes global dimming (1)

allow blocks out sunlight / smog / prevents plant growth / causesbreathing difficulties

or

carbon monoxide (1)

is toxic (1)

or

sulfur dioxide (1)

causes acid rain (1)

allow kills plants / erosion / acidifies water4

[6]

(a) heat to vaporise (the crude oil)

do not accept cracking / burning1

12

vapours condense1

at different temperatures

allow they have different boiling points1

(b) (alkanes) are hydrocarbons or are compounds of hydrogen and carbon only1

alkanes are saturated or have only (carbon-carbon) single bonds

accept have no (carbon-carbon) double bonds

accept general formula is CnH2n+2 for 2 marks1


(c) Marks awarded for this answer will be determined by the Quality of Written Communication(QWC) as well as the standard of the scientific response.

0 marksNo relevant content.

Level 1 (1-2 marks)There is a basic description of at least one advantage or one disadvantage ofextracting petroleum products from oil sands.

Level 2 (3-4 marks)There is a clear description of an advantage and a disadvantage of extractingpetroleum products from oil sands.

Level 3 (5-6 marks)There is a detailed description of both advantages and disadvantages of extractingpetroleum products from oil sands.

Examples of the chemistry/environmental/economic/social points made in theresponse

Advantages:

• the oil sands are needed because crude oil is running out

• this crude oil is needed because demand is increasing

• the oil sands contain a large amount of crude oil

• the oil sands could improve Canada’s economy

• the oil sands provide employment for a lot of people

• the trees / forest are used for wood products / fuel

Disadvantages:

• destruction of environment / habitats

• fewer trees / forests to absorb carbon dioxide

• specified pollution, for example, visual, noise, atmospheric (including dust),water (including river or drinking) with cause, e.g. gases / particulates fromburning diesel

• large amounts of methane (natural gas) are used to provide energy

• energy / fuel needed for cracking and fractional distillation

• burning fuel releases carbon dioxide

• crude oil / natural gas contains locked up carbon

• crude oil is non-renewable6

[11]


(a) (i) wood113

(ii) 30 (kJ)1

(iii) 3 / three (g)1

(b) carbon / C

or hydrogen / H

or sulfur / S

allow oxygen / O1

(c) releases most energy

accept releases a lot of energy / burns rapidly

ignore references to cost1

no harmful gases / no or less pollution formed / no global warming / no climatechange / no greenhouse gas

accept produces water (only) / steam

accept does not produce sulfur dioxide / carbon dioxide / carbonmonoxide / particles / smoke

1

[6]


(a) any two from:

asks for cause therefore no marks for just describing the change

must link reason to a correct change in a gas

carbon dioxide has decreased due to:

accept idea of ‘used’ to indicate a decrease

• plants / microorganisms / bacteria / vegetation / trees

• photosynthesis

ignore respiration

• ‘locked up’ in (sedimentary) rocks / carbonates / fossil fuels

• dissolved in oceans

ignore volcanoes

oxygen has increased due to:

accept idea of ‘given out / produced’

• plants / bacteria / microorganisms / vegetation / trees

• photosynthesis

ignore respiration

nitrogen increased due to:

accept idea of ‘given out / produced’

• ammonia reacted with oxygen

• bacteria / micro organisms

ignore (increase in) use of fossil fuels / deforestation2

14

(b) (because methane’s) boiling point is greater than the average / surface temperatureor Titan’s (average / surface) temperature is below methane’s boiling point

ignore references to nitrogen or water1

any methane that evaporates will condense

accept boils for evaporates

accept cooling and produce rain for condensing1

(c) CnH2n1

[5]

(a) (i) hydrogen / H and carbon / C

answers can be in either order

if letters given, must be capital H1

15

(ii) CnH2n+21


(b) (most) crude oil vaporises / evaporates or crude oil enters as a vapour1

(vapour) cools as it rises up the tower / column or tower / column cooler at the top ornegative temperature gradient

1

the fractions have different boiling / condensation points / ranges

accept the larger the molecules, the higher the boiling point /condensation point

1

so they will condense at different levels in the tower

allow will collect at different levels if condensation mentioned

allow will condense to give different fractions

if no other mark is gained allow 1 mark for mention of heating1

(c) (i) C8H18

if one answer is given C8H18 is the only acceptable answer

credit any correct combination of alkanes and alkenes, eg C5H12

and C3H61

(ii) hot / high temperature

accept any temperature in the range 300 − 900 °C‘heat’ is insufficient

1

catalyst

accept a named catalyst − alumina or zeolites or aluminosilicatesor broken pot

ignore other named catalysts

allow (mixing with) steam as an alternative to second marking pointignore pressure

1

[9]

(a) (i) CH4

allow H4C

do not allow lower-case h

do not allow superscript1

16

(ii) single1

(iii) alkanes1

(b) (i) carbon / C

any order1


hydrogen / H

allow phonetic spelling1

sulfur / sulphur / S1

(ii) air / atmosphere1

(iii) acid rain1

damages trees / plants or kills aquatic organisms or damages buildings /statues or causes respiratory problems

allow harmful to living things1

(c) carbon / C

accept soot / particulates / charcoal1

(d) any four from:

• (supports hypothesis) because when the fuel contained more carbon the temperatureof the water went up more / faster (in 2 minutes)

• (does not support hypothesis as) temperature change per gram decreases as thenumber of carbons increases

• (does not support hypothesis) because the more carbon in the fuel the more smokeor the dirtier / sootier it is

• only tested hydrocarbons / alkanes / fuels with between 5 and 12 carbon atoms• valid, justified, conclusion

accept converse statements4

(e) (i) 0.15

correct answer with or without working gains 2 marks

if answer incorrect, Mr carbon dioxide = 44 gains 1 mark

allow 0.236 / 0.24 / 0.2357142 (ecf from Mr of 28) for 1 mark2

(ii) 0.4(0)1


(iii) C3H8

correct formula with or without working scores 2 marks

0.15 / 0.05 = 3

allow ecf from (e)(i)

and

0.4 / 0.05 = 8 (1)

allow ecf from (e)(ii)

allow 1 mark for correct empirical formula from their values

If use ‘fall-back-values:

0.50 / 0.05 = 10

and

0.20 / 0.05 = 4

1 mark

C4H10

1 mark

if just find ratio of C to H using fall-back values, get C2H5 allow 1mark

2

[19]

(a) oxygen

must be name

do not accept oxide or dioxide1

17

(b) (i) 2 x C–C

and

5 x C–H

all single (line) bonds1

(ii) C3 H8

must be formula

do not accept lower case h1

(iii) water1

(c) ethane and butane boil at temperatures less than 20°C1

ethene and hexene each have a carbon-carbon double bond1

[6]


(a) (i) exothermic

accept combustionallow burning or oxidation or

redox1

18

(ii) carbon monoxide / CO (is produced)

allow monoxide (is produced) ignore carbon oxide1

because there is incomplete / partial combustion (of the fuel)

accept because there is insufficient oxygen / air (to burn the fuel)1

(b) Marks awarded for this answer will be determined by the Quality of WrittenCommunication (QWC) as well as the standard of the scientific response. Examinersshould also refer to the information in the Marking guidance.

0 marksNo relevant content.

Level 1 (1-2 marks)There is a statement that crude oil is heated or that substances are cooled. Howeverthere is little detail and any description may be confused or inaccurate.

Level 2 (3-4 marks)There is some description of heating / evaporating crude oil and either fractions havedifferent boiling points or there is an indication of a temperature difference in thecolumn.

Level 3 (5-6 marks)There is a reasonable explanation of how petrol is or fractions are separated fromcrude oil using evaporating and condensing.


If cracking is given as a preliminary or subsequent process to fractional distillationthen ignore.

However, if cracking / catalyst is given as part of the process, maximum is level 2.

Examples of chemistry points made in the response could include:

• Some / most of the hydrocarbons (or petrol) evaporate / form vapours or gases

• When some of / a fraction of the hydrocarbons (or petrol) cool to their boilingpoint they condense

• Hydrocarbons (or petrol) that have (relatively) low boiling points and arecollected near the top of the fractionating column or hydrocarbons with(relatively) high boiling points are collected near the bottom of the fractionatingcolumn

• The process is fractional distillation

• Heat the crude oil / mixture of hydrocarbons or crude oil / mixture is heated toabout 350°C

• Some of the hydrocarbons remain as liquids

• Liquids flow to the bottom of the fractionating column

• Vapours / gases rise up the fractionating column

• Vapours / gases cool as they rise up the fractionating column

• The condensed fraction (or petrol) separates from the vapours / gases andflows out through a pipe

• Some of the hydrocarbons remain as vapours / gases

• Some vapours / gases rise out of the top of the fractionating column

• There is a temperature gradient in the fractionating column or the fractionatingcolumn is cool at the top and hot at the bottom

6

[9]

(a) (i) hydrocarbons119

(ii) ethane has the smallest molecules1

heptadecane has the highest boiling point1

(iii) evaporating1

condense1

(b) (i) W1


Y1

(ii) floats

if no answer written on line, allow correct answer indicated in thebox

1

(iii) open the tap

allow let the water out

ignore remove water1

stop the flow of liquid when the water has run out

allow until oil is left behind

ignore filter1

[10]

(a) (i) C7H16

mark answer line first

answer may be given in the table1

20

(ii) CnH2n+21

(b) (i) carbon monoxide

do not accept carbon oxide

do not accept water

ignore CO1

(ii) because of partial / incomplete combustion (in reaction 2) or complete combustion (inreaction 1)

allow because there is less / insufficient oxygen (in reaction 2) orsufficient oxygen (in reaction 1) allow different amounts of oxygenused (in the reactions) or 19O2 (in reaction 1) and 13O2 (in reaction2)

ignore air1

(c) (i) 15 (%)

ignore units1

(ii) water (vapour)/steam

allow H2O / OH2 / hydrogen oxide1

(iii) sulfur in petrol / crude oil (reacts with oxygen)

it = sulfur dioxide1


(ii) because nitrogen and oxygen (are in the air and) react

allow nitrogen and oxygen burn

accept nitrogen + oxygen → nitrogen oxide or symbol equation

ignore air1

at high temperature (inside a petrol engine)

allow heat / hot (engine)1

(d) because carbon dioxide / it causes global warming or

allow because carbon dioxide / it causes greenhouse effect /climate change

1

because carbon dioxide / it has an impact on oceans

because this carbon dioxide / carbon / it was ‘ locked up’ (in fossil fuels) or

because the percentage/amount of carbon dioxide / it in the atmosphere is increasing1

[11]

(a) (i) bar drawn between 84 and 86121

(ii) sulfur dioxide linked to acid rain1

carbon particles linked to global dimming1

(b) (i) any one from:

• plants / trees absorb (carbon dioxide)

• coal ‘ locks up’ (carbon dioxide)1

(ii) it increases the amount (of CO2)1

because carbon in coal (forms carbon dioxide)

accept because carbon / coal burns / reacts with oxygen (toproduce CO2)

1

[6]

(a) (i) use of carbon throughout = max 1

burning biodiesel releases CO2

ignore burning trees1

22


CO2 is absorbed / used by the crops/plants (used to produce the biodiesel)

allow CO2 absorbed / used by trees1

(ii) allow use of carbon for carbon dioxide throughout

increases CO2 / greenhouse effect

accept causes global warming

OR

allow causes climate change

less CO2is absorbed (from atmosphere)

ignore other correct effects1

because burning trees releases CO2

accept fewer trees to absorb CO2

or crops / plants do not absorb as much CO2 as trees

ORbecause there is less photosynthesis

ignore habitats / biodiversity

if no other mark awarded global dimming because of smoke /particles gains 1 mark

1

(b) any one from:

ignore carbon neutral / cost / less harmful / environmentally friendly

• crude oil / fossil fuel is running out / non-renewable

allow biodiesel is renewable / sustainable

• demand for fuels / energy is increasing

ignore demand for biodiesel is increasing

• new legislation / protocols1

(c) (i) uses crops / land that could be used for food

allow destroys habitats or reduces biodiversity

ignore cost1

(ii) increases the cost of food / land

ignore cost of machinery / process

ignore cheaper to produce biodiesel1

[7]

(a) carbon dioxide decreased (by plants / trees)

allow plants / trees absorbed carbon dioxide1

23


oxygen increased (by plants / trees)

allow plants / trees released oxygen

if neither of these marks awarded

allow plants / trees

photosynthesise for 1 mark1

because coal ‘locks up’ / traps / stores carbon dioxide / carbon

allow trees ‘locked up’ carbon dioxide / carbon1

(b) carbon / C

hydrogen / H

sulfur / S

all 3 correct 2 marks

1 or 2 correct 1 mark

allow H2

ignore oxygen2

(c) (i) 2 2

balancing must be correct

do not accept changed formulae1

(ii) increases atmospheric pollution

carbon dioxide / CO2 released1

from the (thermal) decomposition of calcium carbonate or

accept causes global warming or CO2 is a greenhouse gas

description of this decomposition or equation

ignore sulfur dioxide and effects in this part1

decreases atmospheric pollution

sulfur dioxide / SO2 is removed

accept less acid rain produced1

by reaction with calcium oxide or calcium carbonate

accept neutralisation or forms calcium sulfate1

[10]

(a) (i) a reasonable attempt at a smooth curve

allow a curve which is close to but does not necessarily touch allpoints

1

24


(ii) any two from:

allow thicker / thinner / runny for viscous

• biodiesel is more viscous than petroleum diesel at all / lowertemperatures

• biodiesel – as the temperature increases the viscosity decreases orvice versa

• petroleum diesel – the viscosity does not change

if no other mark awarded

allow 1 mark for any correct conclusion based on time or rate offlow

2

(iii) does not flow as easily (through pipes / engine)

allow could form a solid / block pipes / engine at low temperatures

or

needs a high temperature to flow

allow more difficult to vaporise / ignite

ignore burning

ignore references to viscosity1

(b) (i) global dimming

allow correct description1

(ii) 56 (%)1

(iii) (increases) acid rain1

because there is more nitrogen oxide(s)

ignore sulfur dioxide


allow 1 mark for nitrogen oxide(s) given1

(iv) answer yes or no does not gain credit because the marks are for an explanation ignore references to petroleum diesel allow carbon for carbon dioxide

no

because carbon dioxide (26%) is released / produced1


this will not all be absorbed by photosynthesis / growing plants for biodiesel

accept growing plants / farming uses machinery / fossil fuelsreleases carbon dioxide

OR

yes

because although carbon dioxide (26%) is released / produced (1)

this was absorbed by photosynthesis / growing plants (for biodiesel) (1)

allow this will be absorbed by photosynthesis / growing plants forbiodiesel

1

[10]

(a) allow answers referring specifically to the naphtha fraction

crude oil is evaporated/vaporised (by heating)1

25

the vapours are condensed (by cooling)1

(fractions condense) / boil at different temperatures

allow fractions have different boiling points1


(b) any four from:

answer yes or no does not gain credit

ignore references to volume of milk held / number of bottles used /biodegradability / habitats / pollution / mining / dust

each marking point must be a comparison

milk bag points

• uses (75%) less crude oil to make (than a plastic milk bottle)

allow eg uses 75% less

poly(ethene) which is made from crude oil

• uses less energy / fuel to make (than a plastic / glass milk bottle)

• produces less carbon dioxide to manufacture (than a plastic / glassmilk bottle)

allow produces less greenhouse gases / causes less globalwarming

allow produces less CO2 on burning

• produces less waste (than a plastic / glass milk bottle)

allow takes up less landfill (space)

allow an argued case for more waste eg milk bags are discarded /cannot be reused

• less fuel used for transport than glass milk bottles

• (produces waste because) milk bags are only used once whereasglass bottles can be re-used

allow milk bags are discarded but glass bottles can be reused (24 /many times)

allow glass bottles can be reused but milk bags can’t

poly(ethene) points

• uses a limited raw material / crude oil whereas the raw materials forglass are almost unlimited

• less (5%) poly(ethene) is recycled (compared to glass (35%))

allow (35%) glass is recycled or (5%) poly(ethene) (bottles)recycled BUT milk bags aren’t / are discarded

or

recycled poly(ethene) is not used to make new bags whereasrecycled glass is used to make new bottles

4

[7]

(a) crude oil / it is evaporated / vaporised

ignore heated1

26


vapours / gases / fractions cool and condense

accept named fraction(s)1

(different) vapours / gases / fractions (condense) at different temperatures

accept (different) vapours / gases / fractions have different boilingpoints

max 2 marks for description of laboratory method or mention ofcracking

1

(b) (i) any one from:

• range of boiling points

• range of carbon atoms1

(ii) greater the number (of carbon atoms) the higher the boiling point

do not accept molecules / particles1

(c) (i) burning / combustion

allow oxidation / redox1

(ii) any two from:

reaction with hydrogen gains max of 1 mark only

• cracking / (thermal) decomposition

• heat / vaporise

• catalyst / aluminium oxide

allow porous pot

ignore names of other catalysts2

[8]


Reused

• saves raw materials / crude oil

• unable to reuse many times

• bags easily split

• saves energy / fuel / transport

• fewer bags needed / made

• reduces carbon / CO 2 emissions

• reduces use of landfill

• saves cost of a new bag

• no waste1

27

Recycled

• saves raw materials / crude oil

• has to be collected / transported / washed / separated /melted

• saves energy / use of fuel

• reduces carbon / CO 2 emissions


• can be used for new products

ignore uses energy1

Burned

• heat / energy released can be used (for heating / generating electricity)

• has to be collected / transported


• wastes the resource / plastic

• releases harmful gases / toxic gases / CO 21


Dumped

• collected / transported with household waste

• wastes the resource

• plastic uses landfill

• (slowly) biodegrades or produces methane which can be used as a fuel

• produces methane which is a greenhouse gas / could causeexplosions

• (not biodegradable so) does not release CO 2 / green house gas into the air

• not biodegradable / take years to decompose

ignore cost / litter / waste / global warming / habitats unless mentioned above1

[4]

(a) carbon / diesel / it reacts / burns in oxygen / air128

limited supply (of oxygen / air)

accept incomplete combustion

2C + O2 → 2CO or

C + CO2 → 2CO gains 2 marks1

(b) any four from:

accept converse statements for fossil diesel.

ignore cost / ease of manufacture / usage issues

for biodiesel:

• less global dimming (because fewer carbon particles)

• less acid rain (because less sulfur dioxide)

if neither point awarded, fewer carbon particles and less sulfurdioxide = 1 mark

• renewable resource / sustainable

accept fossil fuel / diesel supplies are limited

• use waste vegetable oils / fats

• vegetables / plants absorbed carbon dioxide / carbon neutral

accept fossil fuel / diesel releases locked up carbon / is not carbonneutral

• uses land which could be used to produce food

• third world countries can produce bio diesel

• biodegrades easily

• more NOx released4


justified conclusion1

[7]

(a) sulfur dioxide / SO2

allow sulfur oxide1

29

(b) global dimming1

(c) oxygen / O21

(d) (oil is a) limited resource / finite / non-renewable

accept running out of oil or wood is sustainable

accept (burning oil) increases amount of carbon dioxide in theatmosphere / global warming or releases locked up carbon / globaldimming / acid rain

accept the oil (may become) too expensive1

(e) carbon dioxide produced (from burning wood)

ignore global warming1

carbon dioxide used by plants / trees or for photosynthesis


allow carbon emissions used by plants / trees or for photosynthesisfor 1 mark

1

[6]

(a) (i) distillation130

(ii) condense (at different temperatures)

accept they / fractions / hydrocarbons have different boiling points

ignore melting point / size of molecule1

(b) contains hydrocarbons1

has a high boiling point1

(c) C5H121

[5]

(a) complete diagram with 2 carbon atoms and 5 hydrogen atoms each C–Cand each C–H linked by a single line (bond)

1

31


(b) (i) the greater the number of (carbon) atoms (in an alkane molecule) thegreater its boiling point or vice versa

allow as the (carbon) chain gets longer the boiling point increases

ignore melting points

do not accept reference to greater number of molecules1

(ii) they = hydrocarbons from the graph

it = C30H62

any two from:

• low boiling point / volatile

accept they are gases or liquids

• low viscosity

• high flammability

accept easier to burn / ignite

• small molecules

accept short chains

ignore number of carbon atoms

• burn completely

ignore speed of burning2

(c) (i) 16 (CO2) + 18 (H2O)1

(ii) (carbon dioxide in the Earth’s early) atmosphere

accept from volcanoes (millions of years ago)

or from dead plants / animals

allow dead sea creatures

ignore shells1

(iii) increase in burning / use of fossil fuels1

locked up carbon (carbon dioxide) is released

allow carbon / carbon dioxide from millions of years ago is released

accept extra carbon dioxide is not ‘absorbed’ (by the carbon cycle)1

[8]


any four from:

to gain 4 marks both pros and cons should be given

Arguments for biodiesel

max three from:

• sustainable / renewable

• (carbon neutral) absorbs CO 2 when growing / during photosynthesis

• burning biodiesel produces low amounts particulates / carbon monoxide

allow burning biodiesel produces little / low amount of globaldimming

ignore sulfur dioxide

• can use waste vegetable oils / fats (from food industry) or can use waste plant material

• can be used to conserve crude oil (instead of / mixed with petroleum diesel)

• produced by a low energy / temperature process

accept produced by a low tech process

• biodegrades (easily)

ignore engine effects

Arguments against biodiesel

max three from:

• creates food shortages

accept price of food increases

• deforestation to plant more crops leads to loss of habitat / biodiversity or deforestationleads to a reduction in absorption of CO2

allow burning trees increases CO2

allow deforestation increases global warming

• burning biodiesel produces high amounts of nitrogen oxides

allow increases acid rain

• crops takes time to grow

allow crops can fail

• vast areas of land needed to grow crops4

32

conclusion supported by the argument presented, which must give added value to the points forand against given above

1

[5]

(a) elements133


(b) (i) nucleus1

(ii) six1

(c) (i) CH41

(ii) bond1

(d) (i) oxygen1

(ii) any one from:

• (water) does not pollute

accept no harmful gas(es)

allow less pollution

• (only) water is produced

• no carbon dioxide / monoxide (is produced)

accept no greenhouse gas(es) / effect or no global warming1

[7]

(a) acid rain → sulfur dioxide134

global warming → carbon dioxide1

global dimming → carbon particles1

(b) (i) oxygen1

(ii) carbon monoxide1

(c) (i) decreasing

accept running out / none left1


(ii) any two from:

it = coal

• world needs (more) energy

accept population is increasing

allow (greater) demand for coal / fuels / energy

• plentiful supply

accept readily available

allow coal will ‘last longer’

• (many) countries have coal

• easy to find / extract

• oil / gas is running out

accept need to use less oil / gas

accept need to use it to replace oil / gas

• cheap or cheaper than oil2

[8]

(a) (i) straight line through the ‘points’ and extended to C 8H18

do not accept multiple lines1

35

(ii) 5500

range 5400 to 5600

accept ecf from their graph1

(iii) it is a straight line graph

allow directly proportional

accept constant difference between (energy) values

accept C5H12 close to values on the graph

or C5H12 comes in middle of the graph

ignore ‘fits the pattern’ unqualified

ignore ‘line of best fit’

ignore ‘positive correlation’1


(iv) expected ranges for working are:

accept correct numerical answer as evidence of working

(5400 to 5600) – (2800 to 2900) = (2500 to 2800)

or

their value from (a)(ii) – a value from 2800 to 2900

or

(5400 to 5600) / their (a)(ii) divided by 2

or

a value from 2800 to 2900 - 21

no / not quite / almost / yes

this mark is only awarded on evidence from their correct working1

(b) (i) incorrect / no or partially correct

ignore references to hydrogen1

bio-ethanol produces least energy

mark independently

or

bio-ethanol produces 29 kJ1


(ii) ignore incorrect / correct

any two from:

• hydrogen produces only H2O

accept hydrogen does not produce harmful gases / CO2 / SO2

• coal produces SO 2

allow coal causes acid rain / respiratory problems

• coal produces smoke

allow coal causes global dimming

• both renewable and non-renewable fuels produce CO2

accept bio-ethanol and natural gas / coal produce CO2 / globalwarming

• (both) the non-renewable fuels produce CO 2

accept coal and natural gas produce CO2 / global warming

• (both) renewable fuel s produce no smoke

accept hydrogen and bio-ethanol do not produce smoke / globaldimming

• (both) renewable fuel s produce no SO2

accept hydrogen and bio-ethanol

do not produce SO2 / acid rain2

[9]


Name: C7 Organic Chemistryvbio.weebly.com/uploads/2/8/2/4/2824362/c7_organic... · 2020-02-04 ·...

Documents

Transcript of Name: C7 Organic Chemistryvbio.weebly.com/uploads/2/8/2/4/2824362/c7_organic... · 2020-02-04 ·...