Organic Chemistry GCSE CCEA

Fossil Fuels

Formed from dead plants and animals over millions of years under the action of heat and pressure

-Non-renewable

Fossil Fuels Examples

Natural gas, LPG, Petrol, Diesel, Peat, Lignite, Coal coke

Non-renewable resource

Cannot be replaced in a human lifetime, so it will eventually run out

Renewable resource

Can be replaced in a human lifetime e.g. wood

Chemicals obtained from crude oil

Hydrocarbons

Hydrocarbon

A molecule consisting of carbon and hydrogen atoms only

Crude Oil

A liquid mixture of hydrocarbons that includes dissolved gases and solids

Homologous Series

A family of organic molecules that have the same general formula, show similar chemical properties, show a gradation in their physical properties and differ by a 'CH2' unit

Functional group

The reactive part of a molecule

Saturated

No carbon to carbon double bonds

Unsaturated

Contains carbon to carbon double bonds

Crude oil spillages environmental problems

-Destroys habitats

-Harms diving birds

-Creates eyesores on beaches and shorelines

Air Pollution (burning of fossil fuels)

-Carbon dioxide which causes global warming

-Sulfur dioxide which causes acid rain

Alkanes

-Do not have a functional group

-They are all saturated hydrocarbons

- General formula is CnH2n+2

Methane

CH4

Ethane

C2H6

Propane

C3H8

Butane

C4H10

Physical properties of Alkanes

-First 4 members are colourless gases

-Boiling point increases as chain length increases

Chemical reactions of Alkanes

Very unreactive due to the fact that they are saturated and have no functional group

Complete Combustion of Alkanes

Will burn in a plentiful supply of air to give carbon dioxide and water

-Blue flame, non-sooty

Complete Combustion of Alkanes Equations

-CH4 + 2O2 = CO2 + 2H2O

-C2H6 + 3(and)1/2O2 = 2CO2 + 3H2O

Incomplete Combustion of Alkanes

in a limited supply of oxygen will burn to give carbon monoxide (toxic) and water

-Yellow, sooty flame

Incomplete Combustion of Alkanes Equations

-CH4 + 1(and)1/2O2 = CO +2H2O

-C2H6 + 2(and)1/2O2 = 2CO + 3H2O

Alkanes Uses

They burn well, giving out lots of energy, so they are mainly used as fuels

e.g. natural gas is mainly methane, bottled gas is propane and butane

Alkenes

-Functional group is C=C

-They are unsaturated hydrocarbons

-General formula is CnH2n

Ethene

C2H4

Propene

C3H6

Physical properties of Alkenes

-Lower members e.g. Ethene and Propene are colourless gases

-Boiling point increases as chain length increases

Chemical Reactions of Alkenes

Are more reactive than alkanes due to the fact that they are unsaturated

Complete combustion of Alkenes

-Same as for alkanes

-C2H4 + 3O2 = 2CO2 + 2H2O

Incomplete combustion of Alkenes

-Same as for alkanes

-C2H4 + 2O2 = 2CO +2H2O

Bromine Water Test

-Identification test for alkenes

-When Alkanes are shaken with bromine water, the orange colour remains

-When Alkenes are shaken with bromine water, the colour will change from orange brown to colourless

Addition Polymerisation

Small molecules known as monomers, e.g. ethene or chloroethene (vinyl chloride), can join together to make very long chain molecules called polymers

-Ethene = Polythene (poly-ethene)

-Chloroethene (vinyl chloride) = PVC (polyvinylchloride)

Uses of Polymers

Replace many traditional materials (e.g. wood, metal) because they are cheaper and less likely to corrode or rot

Polythene (uses and properties)

-Used in clingfilm, bags, bottles, kitchenware

-it's cheap, strong, easily mauled, waterproof

Polyvinylchloride (PVC) (uses and properties)

- Used for wellington boots, raincoats, drainpipes, electric cables

-It's cheap, flexible, a good insulator, durable and waterproof

Disposal of Polymers

Addition polymers are not biodegradable (cannot be broken down in the environment)

Types of Disposal of Polymers

-Landfill

-Incineration

-Recycling

Landfill Advantages

-Less transport of waste needed

-Land can be re-landscaped after use

Landfill Disadvantages

-Wastes land

-Is an eyesore

-Destroys Habitats

Incineration Advantages

-Less waste going to landfill

-Heat energy can be used to generate electricity

Incineration Disadvantages

-Releases Greenhouse gases

-Ash left is toxic

Recycling Advantages

-Saves raw materials

-Less greenhouse gases

Recycling Disadvantages

-Not always cost effective

-Recycling plants are expensive to build and operate

Carboxylic acids

-Functional group is -COOH

-General formula is CnH2n+1COOH

-First two members are both colourless liquids

-Weak acids (pH3) as they are partially ionised in water

-Weak solution of ethanoic acid is used to flavour food aka vinegar

Methanoic Acid

HCOOH

Ethanoic Acid

CH3COOH

Reaction of Carboxylic Acids with Sodium Carbonate

-Produces CO2 which can be bubbled through limewater, which turns milky white

-Identification test for carboxylic acids

-Observations = Fizzing, white solid disappears, colourless solution formed

Sodium Carbonate + Methanoic acid =

Na2CO3 + 2HCOOH =

= Sodium methanoate + water + carbon dioxide

= 2HCOONa + H2O + CO2

Sodium Carbonate + Ethanoic acid =

Na2CO3 + 2CH3COOH =

Sodium Ethanoate + water + carbon dioxide

2CH3COONa + H2O + CO2

Reaction of Carboxylic Acids with Sodium Hydroxide

-Salt + water are formed

-Observations = heat produced, solution remains colourless

Sodium Hydroxide + Ethanoic acid =

NaOH + CH3COOH =

= Sodium Ethanoate + Water

= CH3COONa + H2O