C9 Crude oil and fuels

Question 1

Alkane

Answer 1

Saturated hydrocarbon with the general formula CnH2n +2, for example methane, ethane and propane. Each carbon atom forms four single covalent bonds.

Question 1

Alkene

Answer 1

Unsaturated hydrocarbon with a carbon-carbon double bond, its general formula is CnH2n

Question 2

Cracking

Answer 2

The reaction used in the oil industry to break down large hydrocarbons into smaller, more useful ones

Question 3

Distillation

Answer 3

Separation of a liquid from a mixture by evaporation followed by condensation

Question 4

Double bond

Answer 4

A covalent bond made by the sharing of two pairs of electrons

Question 5

Flammable

Answer 5

Easily ignited and capable of burning rapidly

Question 6

Fraction

Answer 6

Hydrocarbons with similar boiling points separated from crude oil

Question 7

Fractional distillation

Answer 7

A way to separate liquids from a mixture of liquids by boiling off the substances at different temperatures, then condensing and collecting the liquids

Question 8

Hydrocarbon

Answer 8

A compound with only hydrogen and carbon

Question 9

Mixture

Answer 9

When some elements/compounds are mixed together, but do not react together. Mixtures are not pure substances.

Question 10

Oxidised

Answer 10

A substance that has oxygen added to it/it has lost electrons

Question 11

Saturated hydrocarbon

Answer 11

A hydrocarbon with only single bonds between its carbon atoms, contains as many hydrogen atoms as possible in each molecule

Question 12

Thermal decomposition

Answer 12

The breakdown of a compound by heating it

Question 13

Unsaturated hydrocarbon

Answer 13

A hydrocarbon whose molecules contain at least one carbon - carbon double bond

Question 14

Viscosity

Answer 14

A liquid’s thickness/resistance to flowing or pouring

Question 15

Homologous series

Answer 15

A group of organic compounds that react in a similar way e.g. alkanes and alkenes

Question 16

First four alkanes

Answer 16

Methane: CH4
Ethane: C2H6
Propane:C3H8
Butane: C4H10

Question 17

How does the length of the carbon chain affect the properties of a hydrocarbon?

Answer 17

The shorter the carbon chain, the more runny and less viscous a hydrocarbon is.
The shorter the carbon chain, the more volatile hydrocarbons are(they have lower boiling points).
The shorter the carbon chain, the more flammable(easier to ignite) the hydrocarbon is.

Question 18

Equation for the complete combustion of a hydrocarbon

Answer 18

Hydrocarbon + oxygen: carbon dioxide + water vapour + energy

Question 19

Waste products in complete combustion of a hydrocarbon

Answer 19

Carbon dioxide and water

Question 20

How was crude oil formed

Answer 20

Crude oil is a fossil fuel formed from the remains of plants/animals like plankton that died millions of years ago and were buried in mud. Over millions of years, with high temperature and pressure, the remains turned to crude oil, which are drilled up from the rocks it’s found

Question 21

Finite resources

Answer 21

Non-renewable Resources that will run out as they aren’t formed quickly enough to be considered replaceable, fossil fuels like coal, oil and gas

Question 22

Crude oil

Answer 22

A mixture of lots of different hydrocarbons, most of which are alkanes

Question 23

Stages of fractional distillation

Answer 23

1) Oil is heated until it turns into gas. The gases enter a fractionating column(and the liquid bit is drained off).
2) In the column there’s a negativemtemperature gradient(it’s hotter at the bottom and gets cooler as you go up).
3) The longer hydrocarbons have high boiling points. They condense into liquids and drain out of the column early on, when they’re near the bottom. The shorter hydrocarbons have lower boiling points, so condense and drain out later on, near the top of the column where it’s cooler.
4) You end up with the crude oil mixture being separated into different fractions, each fraction has a mixture of hydrocarbons with a similar number of carbon atoms, so have similar boiling points. These fractions have different boiling points so condense at different places in the tower

Question 24

Organic compounds

Answer 24

Compounds containing carbon atoms

Question 25

Short-chain hydrocarbon uses

Answer 25

Are flammable so are useful fuels e.g. petrol for cars and paraffin for jet fuel and are in high demand as well was kerosene

Question 26

Uses of crude oil

Answer 26

Oil provides fuel for modern transport The petrochemical industry uses hydrocarbons as feedstock to make new compounds for use in things like polymers, solvents, lubricants and detergents Used as fuels e.g. petrol for cars, paraffin for jet fuel,

Question 27

Cracking

Answer 27

How longer alkane molecules produced by fractional distillation are turned into smaller, more useful ones. It's a thermal decomposition reaction as it involves breaking molecules down by heating them.

Question 28

Uses of alkenes

Answer 28

Alkenes are more reactive than alkanes. They're used as a starting material when making other compounds and can be used to make polymers.

Question 29

How does bromine water test for alkenes

Answer 29

1) When orange bromine water is added to an alkane, no reaction will happen and it'll stay bright orange, 2) If it's added to an alkene the bromine reacts with the alkene to make a colourless compound, so the bromine water is decolourised

Question 30

Long-chain hydrocarbon uses

Answer 30

Heavy fuel oil(heating oil/fuel oil/lubricating oil)

Question 31

Catalytic cracking

Answer 31

1)Vaporise long-chain hydrocarbons by heating them. 2)The vapour is passed over a hot powdered aluminium oxide catalyst. 3) The long-chain molecules split apart on the surface of the specks of catalyst - this is catalytic cracking.

Question 32

Steam cracking

Answer 32

You can crack hydrocarbons by vaporising them, mixing them with steam and heating them to a very high temperature.

Question 33

Why is carbon monoxide dangerous

Answer 33

It's a toxic chemical It binds to the blood and reduces its ability to carry oxygen

Question 34

Uses of short hydrocarbon molecules

Answer 34

To make alkenes and polymers

Question 35

Difference in reactivity between alkenes and alkanes

Answer 35

Alkenes are more reactive than alkanes

Question 36

In an investigation of the energy released by the combustion of hydrocarbon fuels, what black substance is at the bottom of the beaker?

Answer 36

Carbon soot

Question 37

Displayed formula of methane

Answer 37

H | H- C- H | H

Question 38

Gases formed in complete combustion of a hydrocarbon(test)

Answer 38

Carbon dioxide turns limewater cloudy The water turns blue cobalt chloride paper pink

Question 39

What happens to the carbon and hydrogen when it's burned?

Answer 39

They're oxidised

Question 40

Volatility

Answer 40

How easily a substance vaporises

Question 41

Why does viscosity increase with increasing hydrocarbon chain length?

Answer 41

It's more difficult to separate/untangle larger masses when heated and convert them into a gas

Question 42

Flammability

Answer 42

How easily a substance combusts

Question 43

How does hydrocarbon chain length affect flammability?

Answer 43

Flammability decreases with increasing hydrocarbon chain length due to the large molecular masses making it difficult for oxygen to react with them at lower temperatures

Question 44

Flames in alkanes

Answer 44

Small alkanes burn with a clean flame, but large alkanes burn with a smoky flame

Question 45

Uses of bitumen fraction

Answer 45

Used for road surfacing and roofing/flooring

Question 46

Products of incomplete combustion

Answer 46

Carbon monoxide, unburnt hydrocarbon and soot

Question 47

How are nitrogen oxides formed?

Answer 47

Reaction of N2 in air with O2 in air at very high temperatures

Question 48

Problems of nitrogen oxides

Answer 48

Acid rain

Question 49

How is sulfur dioxide formed!

Answer 49

Combustion of sulfur(reaction with oxygen) in fuel

Question 50

Problems of sulfur dioxide

Answer 50

Acid rain

Question 51

Ways to reduce problem of sulfur dioxide

Answer 51

Remove sulfur from fuel before burning/remove sulfur dioxide from fumes after burning(flue gas desulfurisation)

Question 52

Ways to reduce problem of nitrogen oxides

Answer 52

For engines use a catalytic converter

Question 53

Ways to reduce carbon monoxide problem

Answer 53

Ensure there's a good supply of air/oxygen when burned

Question 54

Problems of carbon

Answer 54

Blackens buildings Global dimming Formed: Incomplete combustion(reaction with oxygen) of carbon in fuel

Question 55

How to reduce problem of carbon monoxide

Answer 55

Ensure there's a good supply of air/oxygen when burned

Question 56

Unburned fuel

Answer 56

Formed when not all fuel burns, harmful and a greenhouse gas, ensure the correct fuel/air mixture when fuel is burned

Question 57

What does sulfur dioxide react with in flue gas desulphurisation to be removed?

Answer 57

CaO or CaCO3

Question 58

Problem of acid rain

Answer 58

Damages trees/plants Respiratory problems Damages buildings/statues