C1 - Crude Oil

Question 1

What is a mixture?

Answer 1

A mixture consists of multiple elements or compounds that aren’t chemically bonded to each other

Question 2

What are hydrocarbons?

Answer 2

Fuels made from carbon and hydrogen

Question 3

How do we separate all of the different hydrocarbons in crude oil?

Answer 3

Fractional distillation

Question 4

What is the place where fractional distillation happens called?

Answer 4

The fractionating column

Question 5

Describe how fractional distillation works

Answer 5

Crude oil is put into the bottom of the column and the bottom is heated

The vapourised oil travels up the column and condenses in fractions of different heights depending on the type of hydrocarbon (the temperature decreases as you go up the column)

Every fraction has an outlet where its type of hydrocarbon can be let out

At the top of the column, the refinery gas is collected (this still hasn’t condensed)

Question 6

List all of the types of hydrocarbons outputted from the column from bottom to top

Answer 6

Bitumen (road material)

Oil

Diesel

Kerosene (jet fuel)

Naphtha

Petrol

Refinery gas (bottled gas)

Question 7

What decides where a hydrocarbon will condense?

Answer 7

The length of the molecule

The longer the molecule, the higher the temperature when it condenses

Question 8

What are alkanes?

Answer 8

Chains of carbon atoms surrounded by hydrogen atoms

Question 9

What are the first 4 alkanes?

Answer 9

Methane (natural gas)

Ethane

Propane

Butane

Question 10

What does saturated mean?

Answer 10

When all atoms have made bonds with as many other atoms as they can

Only single bonds

Question 11

What is the formula that tells us how many hydrogens or carbons there are in an alkane?

Answer 11

The number of carbons is n

The number of hydrogens is 2n+2

Question 12

What are the 3 basic trends of hydrocarbons?

Answer 12

The shorter the molecules, the less viscous (less gloopy) it is

The shorter the molecules, the more volatile it is (turn into gas at lower temperature)

The shorter the molecules, the more flammable it is

Question 13

Why is refinery gas suitable for use as bottled gas?

Answer 13

Its volatility allows it to be used as a gas at room temperature

Question 14

Why is petrol suitable for car fuel?

Answer 14

A liquid can be stored in the engine easily

It is easily vaporised so it can mix with the air before ignition

Question 15

What are very viscous hydrocarbons used for?

Answer 15

Lubricating engine parts and covering roads

Question 16

Give 4 advantages of crude oil

Answer 16

Burned to make energy and heat for homes

Make chemicals and plastics

Easiest and cheapest to use because things are made to use these fuels

Very reliable

Question 17

What are the 3 disadvantages of crude oil?

Answer 17

It is limited and unsustainable

Burning them creates pollution

The ways that we obtain crude oil can scar the landscape

Question 18

What is crude oil?

Answer 18

A mixture of different hydrocarbons

Question 19

What are the 2 environmental problems with crude oil?

Answer 19

Oil spills can cause damage to animals

Burning it to release energy causes global warming, global dimming and acid rain

Question 20

What is the chemical equation for burning a hydrocarbon?

Answer 20

Hydrocarbon + oxygen

–> carbon dioxide + water vapour

Question 21

How does burning hydrocarbons cause acid rain?

Answer 21

The sulphur impurities in the oil is released as sulphur dioxide when the fuel is burned

Question 22

When are nitrogen oxides released when burning hydrocarbons?

Answer 22

When the combustion is taking place at high temperature

Question 23

What is complete combustion?

Answer 23

When there is enough oxygen and all of the fuel is burned

Question 24

What happens when there isn’t enough oxygen and what is this called?

Answer 24

When partial combustion happens, solid particles (particulates) of soot (carbon), unburnt fuel and carbon monoxide are released

Question 25

Describe how acid rain is caused

Answer 25

Sulphur dioxide is released into the air as a by-product of burning hydrocarbons Sulphur dioxide mixes with clouds to form sulphuric acid which falks to the ground as acid rain

Question 26

What are the 2 problems with removing the sulphur from fuels before burning them?

Answer 26

More expensive Uses energy causing the release of more carbon dioxide

Question 27

What are the 2 other ways of reducing sulphur emissions?

Answer 27

Reduce usage of fossil fuels Power stations have acid gas scrubbers to take harmful gases out before fumes are released into the atmosphere

Question 28

What is the problem with releasing carbon dioxide into the atmosphere?

Answer 28

Causes global warming which causes other types of climate change and risk of flooding due to the polar ice caps melting

Question 29

What is global dimming?

Answer 29

The fact that less sunlight has been reaching the surface of the Earth over time

Question 30

What causes global dimming?

Answer 30

Particles of soot and ash that are produced when fossil fuels are burned reflect sunlight back into space

Question 31

What are the 3 alternative fuels to hydrocarbons?

Answer 31

Ethanol Biodiesel Hydrogen gas

Question 32

How is ethanol made and what are the advantages and disadvantages?

Answer 32

Made by fermentation of plants Carbon dioxide released was taken in by the plant as it grew and the only other product is water Engines need to be converted to work with ethanol and it isn't widely available

Question 33

How is biodiesel made and what are its advantages and disadvantages?

Answer 33

Produced from vegetable oils Carbon neutral, engines don't need conversion, produces hardly any sulphur dioxide or particulates Can't be made fast enough to replace diesel and it is expensive to make

Question 34

How is hydrogen gas made and what are its advantages and disadvantages?

Answer 34

Electrolysis of water Combines with oxygen in the air to form water Expensive engine, need energy from another source to make it, hard to store because it's explosive

Question 35

What is cracking?

Answer 35

Splitting up long-chain hydrocarbons into more desirable short-chain hydrocarbons

Question 36

What 2 products do we usually get from cracking?

Answer 36

Fuels like petrol and paraffin Simple hydrocarbons like ethene which is needed for making plastics

Question 37

What does cracking turn diesel into?

Answer 37

Petrol, paraffin and ethene

Question 38

What type of reaction does cracking use?

Answer 38

Thermal decomposition

Question 39

Describe the procedure of cracking

Answer 39

The long-chain hydrocarbon is heated until it is vapourised The vapour is passed over the powdered catalyst which is aluminium oxide at a temperature of 400 to 700 degrees C The long-chain molecules split apart on the surface of the specks of aluminium oxide

Question 40

How do branching chains or lined-up chains affect a plastic?

Answer 40

Branching chains are softer, easier to melt and lower density