Intensive Class Chemistry SPM

8/10/2019 Intensive Class Chemistry SPM

1/30

19/12/2014 Prepared By

Sir HONG BOON LIANG

What you need? Module

Spot Questions

Intensive Class

Intensive Class Chemistry SPM


2/30

2

Module page 22 number 8

- The melting point of sodium chloride is high because the

electrostatic forces between ions are strong. 1m + 1m

- The melting point of tetrachloromethane is low because the Van Der

Waals forces between molecules are weak. 1m + 1m- Sodium chloride can conduct electricity in molten state or aqueous

solution because it has free moving ions. 1m + 1m

- Tetrachloromethane cannot conduct electricity because it has

molecules. 1m + 1m

Sodium chloride, NaCl is an ionic compound while tetrachloromethane, CCl4 is

a covalent compound. These compounds have different physical properties.

Compare and explain the differences between the two compounds based on:

Melting point

Electrical conductivity [8 marks]

http://www.facebook.com/Sir HONG Chemistry Group


3/30


4/30

4


- The electron arrangement of magnesium atom is 2.8.2. 1m

- Magnesium atom releases 2 valence electrons to form magnesium

Ion. Magnesium ion achieves an octet electron arrangement. 1m

- The electron arrangement of chlorine atom is 2.8.7. 1m- Chlorine atom receives 1 electron to form chloride ion. Chloride ion

achieves an octet electron arrangement. 1m

- One magnesium atom releases two valence electrons to two chlorine

atoms. 1m

- Strong electrostatic force pulls the magnesium ion and chloride ions

together. 1m

- Drawing 1m

Magnesium reacts with chlorine to form an ionic compound,

magnesium chloride. Describe the formation of the compound. Proton

number of Mg = 12, Cl = 17. [7 marks]



5/30

5

Module pages 49, 50 spot questions number 13

- Sulphuric acid produced from contact process. 1m

- Sulphur is burnt in air to produce sulphur dioxide. 1m

- S + O2 SO2 1m

- Sulphur dioxide is burnt in excess oxygen to produce sulphur

trioxide with the presence of vanadium(V) oxide, 450 550 C and

pressure 1 atm. 1m + 1m

- 2SO2 + O2 2SO3 1m

- Sulphur trioxide is dissolved in concentrated sulphuric acid to

produce oleum. 1m

- SO3 + H2SO4 H2S2O7 1m- Oleum is dissolved in water to produce sulphuric acid. 1m

- H2S2O7 + H2O 2H2SO41m

Explain the industrial preparation of sulphuric acid. [10 marks]



6/30

6

Materials

- Sodium thiosulphate solution 0.5 mol dm-3 1m

- Sulphuric acid 1.0 mol dm-3 1m

Apparatus

- 100 cm3

measuring cylinder, 10 cm3

measuring cylinder, 250 cm3

conical flask, stopwatch, paper 1m

Procedure

1. Measure 50 cm3 of sodium thiosulphate solution using 100 cm3

measuring cylinder and poured into a conical flask. 1m

2. Place the conical flask on a piece of paper marked with X. 1m

3. Measure 5 cm3 of sulphuric acid using 10 cm3 measuring cylinder

and add into the conical flask. 1m

4. Start the stopwatch quickly. 1m

Describe one laboratory experiment to study the effect of concentration on the rate of

reaction. Your answer should include the following:

List of materials and apparatus

Procedure of the experiment

Sketch a graph to show the relationship between concentration and rate of reaction

[12 marks]



7/30

7

5. Stop the stopwatch when the X mark disappear from sight. 1m

6. Record the time taken. 1m

7. Repeat steps 1 to 6 using different concentration of sodium

thiosulphate solution. 1m

Max 5m

Chemical equation of the reaction

Na2S2O3 + H2SO4 Na2SO4 + S + SO2 + H2O 1m + 1m

Concentration of

Na2S2O3, mol dm-3

1 / time, s-1 1m +1m

Describe one laboratory experiment to study the effect of concentration on the rate of

reaction. Your answer should include the following:

List of materials and apparatus


Sketch a graph to show the relationship between concentration and rate of reaction

[12 marks]



8/30

8

Module pages 39, 40 number 9

- NaOH + HCl NaCl + H2O 1m

- 50 cm3 of 1.0 mol dm-3 sodium hydroxide solution is measured and

poured into a conical flask. 1m

- Add 3 drops of phenolphthalein indicator into the conical flask. 1m- Filled a burette with 1.0 mol dm-3 hydrochloric acid and record the

initial reading of burette. 1m

- Add the hydrochloric acid slowly into the conical flask until pink

colour solution turns colourless and record the final reading of

burette. 1m + 1m

Neutralization reaction between acid and alkali can be used to produce

soluble salt. By using a suitable acid and alkali, describe how you can

prepare a pure sample of soluble salt by using neutralization reaction.

[12 marks]



9/30

9

- Repeat the experiment by adding the same volume of sodium

hydroxide solution and hydrochloric acid without using

phenolphthalein indicator to get pure salt. 1m + 1m

- The mixture is then heated in a evaporating dish until saturated. 1m

- The saturated solution is cooled to room temperature. 1m- White salt crystals, sodium chloride are filtered. 1m

- White salt crystals are dried between filter papers. 1m

Neutralization reaction between acid and alkali can be used to produce

soluble salt. By using a suitable acid and alkali, describe how you can

prepare a pure sample of soluble salt by using neutralization reaction.

[12 marks]



10/30

10

Module pages 43, 44

Test for copper(II) ion, Cu2+

- Solid of copper(II) nitrate salt is dissolved in water. 2 cm3 of

copper(II) nitrate solution is poured into a test tube. 1m

- Add a few drops of sodium hydroxide solution until excess into atest tube. 1m

- Blue precipitate is formed. 1m

- Blue precipitate insoluble in excess sodium hydroxide solution. 1m

You are given a sample of solid copper(II) nitrate salt.

Describe a chemical test that can be used to verify the presence of

copper(II) ions and nitrate ions in copper(II) nitrate salt. [8 marks]



11/30

11

Test for nitrate ion, NO3-

- 2 cm3 of copper(II) nitrate solution is poured into a test tube. Add

2 cm3 of dilute sulphuric acid into a test tube. 1m

- Add 2 cm3 of iron(II) sulphate solution to the mixture. 1m

- Add slowly concentrated sulphuric acid through the wall of the testtube. 1m

- Brown ring is formed. 1m

You are given a sample of solid copper(II) nitrate salt.

Describe a chemical test that can be used to verify the presence of

copper(II) ions and nitrate ions in copper(II) nitrate salt. [8 marks]



12/30

12


- Soap molecules dissolve in water and decrease the surface tension

of water. 1m

- Soap molecules increase the wetting ability of water. 1m

- Soap molecules consist of hydrophilic and hydrophobic parts. 1m

- Hydrophilic parts dissolve in water. 1m

- Hydrophobic parts dissolve in grease. 1m

- Scrubbing breaks the grease into small droplets. 1m

- Droplets suspended in water to form an emulsion. 1m

- Rinsing washes away the droplets. 1m

1m + 1m

Describe the cleansing action of soap on the stained cloth. [10 marks]



13/30

13

Module page 10 number 9 (a) (d)


Acid reacts with reactive metal to produce salt and hydrogen gas.1m

- 10 cm3 of 1.0 mol dm-3 hydrochloric acid is poured into a test tube.

Add 2 g of zinc powder into a test tube. 1m- Place a lighted wooden splinter at the mouth of the test tube and

pop sound produced. 1m


Zn + 2HCl ZnCl2 + H2 1m +

1m

Describe two methods to verify the solution is an acid. In your answer,

include example of an acid and chemical equation for the reactions

involved. [10 marks]



14/30

14

Acid reacts with metal carbonate to produce salt, carbon dioxide gas

and water. 1m

- 10 cm3 of 1.0 mol dm-3 hydrochloric acid is poured into another test

tube. Add 2 g of calcium carbonate powder into a test tube. 1m

- Pass through the gas released into lime water and lime water turnscloudy. 1m


CaCO3 + 2HCl CaCl2 + CO2 + H2O 1m +1m

Describe two methods to verify the solution is an acid. In your answer,

include example of an acid and chemical equation for the reactions

involved. [10 marks]



15/30


16/30

16


- The electron arrangement of a chlorine atom is 2.8.7. 1m

- A chlorine atom is unstable atom. 1m

- The valence shell of a chlorine atom needs one electron to achieve

an octet electron arrangement. 1m- Two chlorine atoms share one pair of electrons to form one single

covalent bond. 1m

Explain why chlorine exists as diatomic molecule at room temperature.

[4 marks]



17/30


18/30

18

Procedure

1. Put one spatula of solid potassium manganate(VII) in a boiling tube.

1m

2. Put some glass wool into the boiling tube. 1m

3. Clamp the boiling tube horizontally. 1m4. Place one spatula of magnesium powder on a piece of asbestos

paper and put into the boiling tube. 1m

5. Heat the magnesium powder strongly. 1m

6. Then heat the solid potassium manganate(VII). 1m

7. Repeat the experiment using copper powder. 1m

Metals react with oxygen gas to form a metal oxide. Plan one laboratory experiment to

compare the reactivity of two named different metals when react with oxygen gas. Your

answer should include the following:


Observations

A labelled diagram showing the apparatus set-up [12 marks]



19/30

19

Observations

- Magnesium powder burns brightly with a white flame. The white

solid is formed. 1m

- Copper powder glows dimly. The black solid is formed. 1m

- Magnesium is more reactive than copper. 1m Diagram 1m + 1m

Metals react with oxygen gas to form a metal oxide. Plan one laboratory experiment to

compare the reactivity of two named different metals when react with oxygen gas. Your

answer should include the following:


Observations

A labelled diagram showing the apparatus set-up [12 marks]



20/30

20


Materials

- Ethanol, ethanoic acid, concentrated sulphuric acid 1m

Procedure

1. Pour 5 cm3 ethanol into a boiling tube and add 5 cm3 of ethanoicacid. 1m

2. Add 3 drops of concentrated sulphuric acid into a boiling tube. 1m

3. Heat the mixture carefully using a small flame. 1m

4. Boil the mixture slowly about 3 minutes under reflux. 1m

5. Pour the contents of the boiling tube into the beaker containing

water and smell the contents of the beaker. 1m

Describe a laboratory experiment to prepare an ester by using named alcohol and named

carboxylic acid. Your answer should include the following:

A list of materials


Observation and chemical equation

Name of the ester produced [10 marks]



21/30


22/30


23/30

23

3. Immersed the carbon electrodes to each arm and connect to the

galvanometer using connecting wire. 1m

4. Record the observations.

ObservationsElectrode in potassium iodide solution / Anode

- Colourless potassium iodide solution changes to purple. 1m

Electrode in bromine water / Cathode

- Brown colour of bromine water changes to colourless.1m

By using potassium iodide solution and a suitable oxidizing agent, describe a laboratory

experiment of a redox reaction in U-tube. Your answer should include the following:

Half equations involved


Observations

A labelled diagram [10 marks]



24/30

24

Diagram 1m + 1m

By using potassium iodide solution and a suitable oxidizing agent, describe a laboratory

experiment of a redox reaction in U-tube. Your answer should include the following:

Half equations involved


Observations

A labelled diagram [10 marks]


Dilute sulphuric acid

Bromine waterPotassium iodide

solution

Carbon electrode Carbon electrode


25/30

25

Module page 27 number 12 (b)

1.0 mol dm-3 sodium chloride solution

- Chloride ions selected to discharge at anode. 1m

- Concentration of chloride ions is higher than hydroxide ions. 1m

- Greenish-yellow gas bubbles are released. 1m- The product is chlorine gas. 1m

0.001 mol dm-3 sodium chloride solution

- Hydroxide ions selected to discharge at anode. 1m

- Hydroxide ions is lower than chloride ions in electrochemical series.

1m

- Colourless gas bubbles are released. 1m

- The product is oxygen gas. 1m

Explain the observations at anode for the electrolysis of 1.0 mol dm-3

sodium chloride solution and 0.001 mol dm-3 sodium chloride solution

using carbon electrodes. [8 marks]



26/30

26

Module page 27 number 12 (c)

Carbon electrodes

- Hydroxide ions selected to discharge at anode. 1m

- Hydroxide ions is lower than nitrate ions in electrochemical series.

1m

- Colourless gas bubbles are released. 1m

- The product is oxygen gas. 1m

Silver plates

- Silver plate dissolves in silver nitrate solution at anode. 1m

- Silver plates are active electrodes which take part in chemical

reaction. 1m- Silver plate at anode becomes thinner. 1m

- The product is silver ion. 1m

Explain the observations at anode for the electrolysis of 1.0 mol dm-3

silver nitrate solution using two carbon electrodes and two silver plates.

[8 marks]



27/30


28/30

28

9. Weigh the lamp as quickly as possible and record the final mass.

1m

Max 5m

Result

Initial temperature of the water / C = T1Highest temperature of the water / C = T2Temperature rise of water / C = T2 T1

1m

Initial mass of lamp + ethanol / g = m1

Final mass of lamp + ethanol / g = m2Mass of ethanol that was burnt / g = m1 m2 1m

Describe an experiment that you can carry out in your school

laboratory to determine the heat of combustion of ethanol. Your

description should include precautionary steps and the steps involved

in the calculation. [12 marks]



29/30

29

Calculation

Heat released, Q = 200 g 4.2 J g-1 C-1 (T2 T1) C1m

Number of moles of ethanol = (m1 m2) g / 46 g mol-1 1m

Heat of combustion, H = 200 g 4.2 J g-1 C-1 (T2

T1

) C

(m1 m2) g / 46 g mol-1

1m

Diagram 1m + 1m

Describe an experiment that you can carry out in your school

laboratory to determine the heat of combustion of ethanol. Your

description should include precautionary steps and the steps involved

in the calculation. [12 marks]



30/30

30

GOOD LUCK !!!


A+ Chemistry

Thank You

Intensive Class Chemistry SPM

Documents

Transcript of Intensive Class Chemistry SPM