F322 basic concepts and hydrocarbons - The Student Room

F322 Chains Energy and Resources

Module 1 Basic Concepts amp Hydrocarbons

bull Empirical Formula The simplest ratio of atoms of each element present in a compound

bull Molecular formula The actual number of atoms of each element present in a compound

bull General Formula The simplest algebraic formula of a member of a homologous series eg Alkanes general formula is CnH2n+1

bull Structural Formula The minimal detail that shows the arrangement of atoms in a molecule eg for butane CH3CH2CH2CH3 or CH3(CH2)2CH3

bull Displayed Formula The relative positioning of atoms and the bonds between them ie for ethanol

bull Skeletal Formula The simplified organic formula shown by removing hydrogen atoms from alkyl chains leaving just a carbon skeleton and associated functional groups ie for butan-2-ol

OH

H

H

H

H

H

OH



bull Homologous series A series of organic compound shaving the same functional group but with each successive member differing by CH 2

bull Functional Group A group of atoms responsible for the characteristic reactions of a compound

Alkanes Homologous Series

Number of carbons Name Formula

1 Methane CH4

2 Ethane C2H6

3 Propane C3H8

4 Butane C4H10

5 Pentane C5H12

6 Hexane C6H14

7 Heptane C7H16

8 Octane C8H18 9 Nonane C9H20

10 Decane C10H22

bull Hydrocarbon A compound of carbon and hydrogen only

bull Saturated Hydrocarbon A hydrocarbon with single bonds only

bull Unsaturated Hydrocarbon Contains carbon-carbon multiple bonds

bull Aliphatic hydrocarbon A hydrocarbon in which the carbon atoms are joined together in unbranched or branched chains

bull Alicyclic Hydrocarbon A hydrocarbon in which the carbons are joined together in a ring structure

Carbon is in group 4 of the periodic table it has 4 electrons in the outer shell which pair up

with electrons in other atoms to form 4 covalent bonds

Alkanes re saturated hydrocarbons with single C-C bonds only Each carbon atom is bonded to

four other atoms Each carbon has a tetrahedral shape (1095)



A

C C

H

H A

A

C C

A

H H

B

C C

A

A C

A

C C

A

C B

bull Structural Isomers Compounds with the same molecular formula but different structural formula

bull Stereoisomers Compounds with the same structural formula but with a different arrangement in space

bull EZ isomerism An example of stereoisomerism in terms of restricted rotation about a double bond and the requirement for two different groups to be attached to each carbon atom of the C=C group E Isomerism Z Isomerism

bull Cis-trans isomerism A special case of EZ isomerism in which two substituent groups are the same

CIS TRANS

oppositE

Together



Type of Compound Formula Prefix Suffix

Alkane C-C -ane Alkene C=C -ene Halogenoalkane -F

-CL -Br -I

Fluoro- Chloro- Bromo- Iodo-

Alcohol -OH -ol Aldehyde -CHO

-al

Ketone C-CO-C

-one

Carboxylic acid -COOH

-oic acid

O

C

OH

C C C

O

O

C

H



During a chemical reaction bonds are broken in a process called bond fission A covalent

bond can be broken in two ways

bull Homolytic Fission

1 Each bonded atom takes one of the shared pair of electrons

2 Each atom now has an unpaired electron and is called a radical

3 Two species of the same type (lsquohomorsquolytic) are produced

X ndash Y -----gt X + Y

bull Heterolytic Fission

1 One of the bonded atoms takes both of the electrons in the shared pair

2 Two ions are produced

3 The atom that takes both electrons becomes negatively charged (anion)

4 The atom that does not take the shared electron becomes positively charged

(cation)

X ndash Y -----gt X+ + Y-

bull Nucleophile An electron pair donor

bull Electrophile An electron pair acceptor

bull Addition reaction A molecule is added across the double bond of an unsaturated molecule to make a saturated molecule

2 reactants -----gt 1 product

bull Substitution reaction An atom or group of atoms is replaced with a different atom or groups of atoms

2 reactants -----gt 2 products

bull Elimination Reaction The removal of a molecule from a saturated molecule to make a saturated molecule

1 reactant -----gt 2 products



Percentage Yield

100 yields are rarely achieved possible causes are

bull The reaction may be at equilibrium and may not go to completion

bull Other side reactions may occur leading to by-products

bull The reactants may not be pure

bull Some of the reactants or products may be left behind in the apparatus

bull Separation and purification may result in the loss of some of the product

1313

1313

A Limiting Reagent is the substance in a chemical reaction that runs out first

Atom Economy

A reaction may produce by-products along with the desired product

What can be done with by-products

1 If it is considered to be waste by-products are disposed of This is costly and poses

potential environmental problems

2 By-products may be sold on or used elsewhere in the chemical plant This practice is

likely to increase in the future as we become increasingly concerned about

preserving the earthrsquos resources and minimising waste

Atom economy considers not only the desired product but also the by-products in a chemical

reaction It describes the efficiency of a reaction in terms of all atoms involved High atom economy

means minimal waste

1313 1313

1313

bull Addition reactions 100 atom economy

bull Substitution and Elimination reactions lt 100 atom economy

How can atom economy benefit society

By using products with higher atom economy chemical companies can reduce the amount of waste

produced which is also good for the environment since we a re running out of landfill sites It has

also been suggested that 5-10 of the expenditure of a chemical company goes on waste treatment

bull Percentage yield tells you the efficiency of converting reactants into products

bull Atom economy tells you the proportion of desired products compares with all the products

formed

bull A reaction may have a high percentage yield but a low atom economy



Hydrocarbons from crude oil

Hydrocarbons are organic compounds containing hydrogen and carbon only

Crude oil is a fossil fuel made from naturally decaying plants and animals that once lived in ancient

seas millions of years ago It is a mixture of over 150 different hydrocarbons most of which are

unbranched Crude oil does not ignite easily so is not useful in its native state However some of its

components are valuable and are used in petrol kerosene and heating and lubricating oils

Fractional Distillation - The separation of the components of crude oil into fractions which differ in

boiling point by means of distillation

Crude oil is refined in a distillation plant

1 The mixture of hydrocarbons is separate into fractions

2 Each fraction consists of a mixture of hydrocarbons with similar boiling points

3 Pure liquids have a fixed boiling point A pure hydrocarbon can be obtained by

further distillation of a crude oil fraction

The process takes place in a fractionating column

A The crude oil is vaporised and then passed into the fractionating column The

column is hotter at the bottom than the top and the gases pass up the column

through a series of bubble caps

B Eventually the gases reach a temperature that is lower than their boiling points

Here the vapour condenses to a liquid The liquid fractions are then tapped off into

storage containers

C Short chained hydrocarbons with lower boiling points condense near the top of the

column

D Longer chained hydrocarbons with higher boiling points condense near the bottom

E Gases which do not condense pass through the top of the column as lsquopetroleum gasrsquo

F The residue from the process is bitumen which is removed from the bottom of the

column

G The fractions obtained from crude oil can be used as fuels or may be further

processed to produce petrochemicals

Alkanes and cycloalkanes are saturated hydrocarbons



Boiling Points of Alkanes

VDW forces exist between the different alkane molecules in a fraction which have to be broken in

order for the mixture to boil

$ amp ( ) $(

Chain length increases intermolecular forces stronger boiling point increases More points of

contact between long-chained alkanes so more VDW forces It takes more energy and therefore a

higher temperature to separate the molecules

Isomers have the same molecular mass A branched isomer has a lower boiling point than an

unbranched isomer There are fewer points of contact when branched chains interact with other

molecules so fewer VDW forces between the molecules

Also branched molecules cannot get as close to each other as unbranched one so fewer

intermolecular forces so less energy required to separate the molecules and lower boiling point



Short chain alkanes are valuable as clean fuels They burn in a plentiful supply of oxygen to form

carbon dioxide and water

Methane is the main constituent of natural gas and is used for domestic heating and cooking It

burns cleanly in oxygen

CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)

Propane and butane are easily liquefied and are known as liquefied petroleum gas or LPG They are

used as fuels in barbecues patio heaters and portable cooking appliances

Octane is present in petrol used to fuel internal combustion engines

C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)

Incomplete Combustion

The internal combustion engine in most cars has a limited supply of oxygen so some of the octane

will undergo incomplete combustion forming carbon monoxide instead of carbon dioxide

C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)

CO is a colourless odourless gas produced when a fossil fuel is burned with an insufficient supply of

oxygen It is poisonous prevents the haemoglobin in RBCs from binding with oxygen and the bodyrsquos

tissues become starved of oxygen which can be fatal At home CO can be formed form faulty

heating systems blocked chimneys or inadequate ventilation CO detectors protect the home from

the toxic effects of CO

NB In combustion equations C02 molecules = No of carbon atoms in HC and H2O molecules = -

No

Of hydrogen atoms

After fractional distillation there are lots of long-chained hydrocarbons however there is high

demand for short-chained hydrocarbons for use as a) fuels and b)polymer production

Cracking ndash The breaking down of long-chained saturated hydrocarbons to form a mixture of shorter-

chained alkanes and alkenes

In catalytic cracking long chained alkanes are broken randomly There are many possible equations

for cracking a particular starting material In catalytic cracking the equations must be balanced and a

mixture of alkanes and alkenes is always formed Most catalytic cracking uses a zeolite catalyst at

450degC

Branched Alkanes can be formed by a process called isomerisation which converts unbranched

alkanes into branched alkanes

Cyclic Hydrocarbons can be produced in a process called reforming where aliphatic hydrocarbons

are converted into cyclic or aromatic hydrocarbons hydrogen is also produced



Improving Fuels

The Research Octane Number (RON) rates how well a fuel burns Fuels with high octane ratings close

to 100 burn efficiently Heptane (straight-chained alkane) is a poor fuel and has an RON of 0

Branched and cyclic alkanes are important petrol additives they promote more efficient combustion

that straight-chain alkanes Also branched alkanes are used in fuels for car engines

The hydrogen produced during reforming is used in other chemical processes such as ammonia and

margarine production This is a good example of using by-products to make other useful products

We have come to rely on crude oil as a source of power for electrical generation and for transport

Many chemicals produced from crude oil have become important feedstock for the chemical

industry over 90 of crude oil is used for fuel Every day items can be made from petrochemicals

The Earthrsquos deposits of crude oil are depleting at a fast rate

Many of the fuels produced are alkanes Branched and cyclic alkanes are amongst the best fuels A

good fuel needs to be readily available easily transported and inexpensive Oil is suitable but

recently its price has increased significantly and scientists are now looking into alternatives to fossil

fuels

At the start of this century the publicrsquos opinion and concern for the environment has shifted all

hydrocarbons produce pollutants The over reliance on crude oil as for fuel has led environmentalists

to call for urgent actionso it is not only the price of oil that has caused scientists to look for

alternative forms of energy

Burning hydrocarbons leads to an increase in atmospheric pollutants such as

bull Carbon monoxide ndashToxic gas formed by incomplete combustion in internal combustion

engine

bull Carbon dioxide ndash Major contributor o global warming (greenhouse effect)

bull Nitrogen oxides ndash Contributors to acid rain and destruction of forests

bull Sulphur dioxide ndash Acid rain

Global Warming

Refers to an increase in the Earthrsquos average temperature There is growing evidence that this could

be related to human activity such as burning fossil fuels which releases carbon dioxide and other

greenhouse gases into the atmosphere These gases prevent heat from escaping the atmosphere

and leads to increased temperatures on Earth A warmer planet may mean a change in climate with

heavier rain and more frequent violent storms Temperature change also threatens to melt the

polar ice caps which could result in sea levels rising and localised flooding This will have an impact

on all plant and animal forms and will lead to a change in lifestyle



Fuels for the Future

A biofuel is a fuel that is derived from recently living material such as plants or animal waste

Agricultural crops grown for energy use include sugar cane and rape

Ethanol can be made by fermenting sugar and other carbohydrates It burns efficiently in a plentiful

supply of oxygen to give carbon dioxide and water Ethanol can be blended with petroleum for a fuel

that burns more efficiently Ethanol blends can be used in engines without modifications This

reduces harmful exhaust emissions

Bioethanol is getting a big boost in the UK as the countryrsquos first plants become operational

Biodiesel is a fuel oil derived from natural resources such as plants Rapeseed is the most popular

source in Europe Biodiesel can be used 100 pure in compatible engines however it is normally

blended with normal diesel



Alkanes react with halogens n the presence of UV radiation or at a temperature of 300degC

This reaction is called Radical Substitution ndash A radical replaces a different atom or group of atoms in

a molecule

bull Covalent bonds are broken by homolytic fission to form radicals

bull A hydrogen atom in the alkane is substituted by a halogen atom

Eg methane reacts with chlorine to produce chloromethane

CH4 + Cl2 -----gt CH3Cl + HCl

Mechanism

Initiation

Cl ndash Cl -----gt Cl + Cl

Propagation

1 CH4+ Cl -----gt CH3 + HCl

2 CH3 + Cl2 -----gt CH3Cl + Cl

Termination

Cl + Cl -----gt Cl2

Cl + CH3 -----gt CH3Cl

CH3 + CH3 -----gt C2H6

Further Reactions of Chloromethane

Other organic products can form in the propagation stage

In the termination stage Chlorine Ethane and chloromethane are formed However chloromethane

may react further with chlorine radicals until all of the hydrogen radicals have been replaced which

results in a mixture of chloromethane dichloromethane trichloromethane and tetrachloromethane

The free radicals are generated

by ultraviolet radiation

The two repeated steps that

build up the products in a chain

reaction Propagations reactions

are rapid and continue until no

reactants remain

Two radicals combine to form a

molecule



Limitations of Radicals in Synthesis

Every cell in the body produces tens of thousands of radicals every day they are a by-product of cell

metabolism such as form fighting infection or burning glucose for energy they are important in

hormone and enzyme production

Exposure to radicals is linked to premature aging Radicals can damage cell membranes of all cells

and DNA The body has antioxidants that keep radicals in check and protect the body against the

harmful effects of radicals Antioxidants are vitamins C and E We are also exposed to radicals from

cigarette smoke sunbathing pollution and food contaminated with herbicides



H

H

C C

H

H

Alkenes and cycloalkenes are unsaturated hydrocarbons Alkenes have at least one C=C double

bond Aliphatic alkenes with one double bond have the general formula CnH2n They are more

reactive than alkanes and typically take part in addition reactions They can form EZ isomers

including cis-trans isomers

A π-bond is the reactive part of a double bond formed above and below the plane of bonded atoms

by the sideways overlap of p-orbitals Each carbon atom contributes one electron from a p-orbital to

the electron pair in the π-bond which fixes the carbon atoms in position and prevents any rotation

of the bond In alkenes each carbon uses 3 electrons in 3 σ-bonds and 1 electron in one π-bond

Shape of Alkenes

3 regions of electron density surround each carbon atoms in a double bond Pairs of electrons repel

each other as far apart as possible The electron pairs repel each other to give a trigonal planar

shape (120deg)

Cyclic alkenes can be treated the same as branched or straight chained alkenes ndash the react in the

same way

Alkenes are more reactive than alkanes because of the C=C double bond Bond enthalpies show that

a double bond is stronger than a single bond and a π-bond is weaker than a σ-bond When an alkene

breaks the π-bond breaks and the σ-bond stays intact

H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions

Typically addition reactions

1 A small molecule is added across the double bond causing the π-bond to break

2 2 reactant molecules react together to form on product

3 An unsaturated alkene reacts and forms a saturated alkane

Hydrogenation of Ethene

This is an example of reduction

Halogenation of Ethene

When bromine is added to an alkene sample the colour changes from orange to

colourless The colour change indicates bromine has reacted with the double bond

This is a test for unsaturation it shows the presence of a C=C double bond

Addition of Hydrogen Halides

Hydration of Ethene

A method of preparing alcohols

+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H

Addition of Hydrogen Bromide (electrophilic addition)

+

Hδ+

Brδ-

Br -

Br -

bull In this reaction HBr is

the electrophile

electron pair acceptor

bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes

bull The HBr bond breaks

by heterolytic fission

When bromine is added to an

alkene

bull The electrons in the π-

bond repel those in

the Br-Br bond

inducing a dipole in

Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n

Polymer - A long molecular chain built up from monomer units

Monomer ndash Small molecule that combines with others to form a polymer

If the monomers are alkenes many monomers can be added together to form a long polymer chain

This process is called addition polymerisation

Addition Polymer ndash Very long molecular chain formed by repeated addition reactions of unsaturated

alkene molecules (monomers)

Monomer Polymer (repeated unit)



The Use of Alkenes

Margarine

The word used for a substance to substitute butter It is made from fats mixed with skimmed milk

and salt Margarine from veg oil is becoming popular for good health people are refusing animal fats

in their diets Margarine with high mono- or polyunsaturated fats are said to be healthier than

butterother margarines Often made from sunflowerolive oil

Veg oils are liquids containing long hydrocarbon chains with many double bonds and are

polyunsaturated The oil must be hardened so it can be spread without being soaked into bread

The oils are hardened by hydrogenation which adds hydrogen molecules across double bonds in an

addition reaction It alters the individual molecule so that the oil partially solidifies and hardens By

adding hydrogen molecules across different numbers of double bonds hardness can vary and

spreadability of margarine can be controlled Partial hydrogenation of unsaturated fats can

transform cis double bonds into trans double bonds as a by-product trans fats are thought to be bad

for health

Poly(phenylethene) Polystyrene is a cheap plastic used in foam packaging insulation model-making

and food retail Polystyrene is being replaced with biodegradable materials as environmental

pressure increases

Poly(propene)Polypropylene is used in food packaging dishwasher safe containers carpet fibres

synthetic ropes It is resistant to chemical attack so is used in certain lab equipment

Addition polymers are durable and do not break down naturally which makes them very useful but

their disposal poses problems

Processing of Waste Polymers

The best way to protect the environment is to re-use polymers without processing

Separation into Types and Recycling

Before plastic waste can be processedconverted it must be sorted Polymer ID codes are used to do

this Optical scanning techniques can separate PET from HDPE bottles Other technologies can

distinguish PVC from other plastics A small quantity of PVC in PET can render the product unsuitable

for re-use PVC is known to release poisonous dioxins when heated

Reclamation

This involves mechanically chopping polymers into small flakes then washing them to remove

impurities The flakes are sent to manufacturing companies where new materials are made by

melting the pellets and remoulding them

PET bottles are converted into carpets clothing and new bottles

HDPE is re-used to make plastic boxes water butts and bins

LDPE waste is made into plastic refuse sacks

Polymers as a Fuel Source

Burning polymers produces heat energy which can be harnessed to generate electricity Agricultural

plastics are being turned into briquettes and are being burned for heat



Feedstock Recycling

Processes are being developed to convert polymers into synthesis gas a mixture of H2 and CO which

can be used as chemical feedstock for conversion into useful products or as fuel at oil refineries

Scientists are working to increase the efficiency and cost-effectiveness of feedstock recycling

Recycling PVC - poly(vinyl chloride)

This is problematic because of its high chlorine content Recycling PVC is uneconomical because the

cost of recycling makes the end product more expensive than that made from crude oil

Incineration has been used to prevent PVC going into landfill sites Combustion of PVC releases toxic

fumes into the environment and may cause corrosion in the plant itself HCl fumes are also detected

when PVC is heated to high temps as part of the recycling process Incinerators are equipped with

pollution control apparatus to minimise such emissions New technology ndash PVC is separated from

other scrap by dissolving in solvents High-quality PVC is recovered by precipitation from the solvent

The solvent is recovered and used again This recycles the PVC coatings of wiring and other PVC

waste

Biodegradable and Compostable Polymers

Bioplastics are derived from starch maize cellulose and lactic acid and are biodegradable or

compostable Bioplastics are kinder to the environment and degrade naturally to carbon dioxide and

water

bull Bioplastic breaks down due to bacterial activity

bull Bioplastics have strict criteria must break down by a biological process to CO2 H2O

inorganic compounds and biomass Compostable plastics break down in a similar time frame

as natural compostable materials

bull Bags and cutlery made from cornstarch could replace oil-derived polythene in the future

Supermarket bags can also be made from plant starch and can be used as bin liners to collect

food waste The bag and waste can be composted together

bull Compostable disposable tableware made from sugar cane fibre are replacing polystyrene

products

bull Poly(lactic acid) is used for cold drink cups that biodegrade in 180 days



bull Homologous series A series of organic compound shaving the same functional group but with each successive member differing by CH 2

bull Functional Group A group of atoms responsible for the characteristic reactions of a compound

Alkanes Homologous Series

Number of carbons Name Formula

1 Methane CH4

2 Ethane C2H6

3 Propane C3H8

4 Butane C4H10

5 Pentane C5H12

6 Hexane C6H14

7 Heptane C7H16

8 Octane C8H18 9 Nonane C9H20

10 Decane C10H22

bull Hydrocarbon A compound of carbon and hydrogen only

bull Saturated Hydrocarbon A hydrocarbon with single bonds only

bull Unsaturated Hydrocarbon Contains carbon-carbon multiple bonds

bull Aliphatic hydrocarbon A hydrocarbon in which the carbon atoms are joined together in unbranched or branched chains

bull Alicyclic Hydrocarbon A hydrocarbon in which the carbons are joined together in a ring structure

Carbon is in group 4 of the periodic table it has 4 electrons in the outer shell which pair up

with electrons in other atoms to form 4 covalent bonds

Alkanes re saturated hydrocarbons with single C-C bonds only Each carbon atom is bonded to

four other atoms Each carbon has a tetrahedral shape (1095)



A

C C

H

H A

A

C C

A

H H

B

C C

A

A C

A

C C

A

C B





CIS TRANS

oppositE

Together





-CL -Br -I



-al

Ketone C-CO-C

-one


-oic acid

O

C

OH

C C C

O

O

C

H















(cation)












Percentage Yield







1313

1313


Atom Economy










means minimal waste

1313 1313

1313









formed























storage containers


column




column









$ amp ( ) $(















CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




A

C C

H

H A

A

C C

A

H H

B

C C

A

A C

A

C C

A

C B





CIS TRANS

oppositE

Together





-CL -Br -I



-al

Ketone C-CO-C

-one


-oic acid

O

C

OH

C C C

O

O

C

H















(cation)












Percentage Yield







1313

1313


Atom Economy










means minimal waste

1313 1313

1313









formed























storage containers


column




column









$ amp ( ) $(















CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products






-CL -Br -I



-al

Ketone C-CO-C

-one


-oic acid

O

C

OH

C C C

O

O

C

H















(cation)












Percentage Yield







1313

1313


Atom Economy










means minimal waste

1313 1313

1313









formed























storage containers


column




column









$ amp ( ) $(















CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products
















(cation)












Percentage Yield







1313

1313


Atom Economy










means minimal waste

1313 1313

1313









formed























storage containers


column




column









$ amp ( ) $(















CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




Percentage Yield







1313

1313


Atom Economy










means minimal waste

1313 1313

1313









formed























storage containers


column




column









$ amp ( ) $(















CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products























storage containers


column




column









$ amp ( ) $(















CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products







$ amp ( ) $(















CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products








CH4(g) + 2O2(g) -----gt CO2(g) + 2H2O(l)




C8H18(g) + 12+

O2(g) -----gt 8CO2(g) + 9H2O(l)




C8H18(g) + 8+

O2(g) -----gt 8CO(g) + 9H2O(l)







No

Of hydrogen atoms








450degC







Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




Improving Fuels














fuels







engine




Global Warming

























a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products



















a molecule





Mechanism

Initiation


Propagation



Termination

Cl + Cl -----gt Cl2


CH3 + CH3 -----gt C2H6












reactants remain


molecule













H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products














H

H

C C

H

H









Shape of Alkenes



shape (120deg)


same way




H

H

C C

H

H

P-orbitals overlap

σ-bond σ-bond

π-bond



Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




Ni

150degC

C

H

H C

H

H H

H

H

C C

H

H H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

H

C C

H

H H

C

H

H C

H

Cl Cl

H

Alkene Reactions












Hydration of Ethene


+ H2

+ Cl2

+ HBr

+ H2O(g) H3PO4



H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




H

C C

H

H H

C

H

H C

H

H H

+

C

H

H C

H

H H

+ C

H

H C

H

H Br

H


+

Hδ+

Brδ-

Br -

Br -


the electrophile


bull HBr is a polar

molecule but non-

polar molecules can

also react with

alkenes




alkene


bond repel those in

the Br-Br bond


Br2

bull This forms a

carbocation and a

bromide ion



B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




B

C C

A

E D

n C

H

C

H

Cl Cl n










The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




The Use of Alkenes

Margarine












for health



pressure increases












Reclamation












Feedstock Recycling













waste




water









products




Feedstock Recycling













waste




water









products


F322 basic concepts and hydrocarbons - The Student Room

Documents

Transcript of F322 basic concepts and hydrocarbons - The Student Room