F322-Fuels

Question 0

What is fractional distillation?

Answer 0

A method of separating the crude oil mixture into fractions according to their boiling points

Question 1

What is volatility?

Answer 1

How easily it turns into a gas

Question 2

Where do the more volatile components with lower boiling points go in fractional distillation?

Answer 2

They rise to the top of the fractionating column

Question 3

What can hydrocarbons obtained from crude oil be used directly as?

Answer 3

Fuels or as feedstock for processing into petrochemicals

Question 4

Give a use for propane

Answer 4

Bottled gas

Question 5

What 1-4 carbon alkanes used for?

Answer 5

Bottled gas

Question 6

What are carbon 5-7 alkanes used for?

Answer 6

Petrol

Question 7

What are carbon 6-10 carbon alkanes used for?

Answer 7

Making petrochemicals

Question 8

What 3 points make a good fuel?

Answer 8

~volatile
~easy to ignite
~burns completely in air(no soot)

Question 9

What does catalytic cracking do?

Answer 9

It converts long-chain hydrocarbons into more useful alkanes and alkenes using heat and a catalyst

Question 10

Give an example of cracking

Answer 10

C6H14 > C4H10 + C2H4

Question 11

Suggest 2 reasons why oil companies use catalysts

Answer 11

1- catalysts speed up the reaction without being consumed
2- using a catalyst saves money for the companies as they are cheaper to run and allows a lower temperature to be used so less fuel is needed

Question 12

What does Isomerisation do? State conditions needed

Answer 12

Converts straight chain alkanes into branched alkanes.

Conditions = high temp & platinum catalyst

Question 13

What does reforming do? State conditions needed.

Answer 13

Converts straight chain alkanes into cyclic alkanes and arenes.
Conditions = high temp & platinum catalyst

Question 14

Why are branched alkanes and cyclic hydrocarbons used in petrol?

Answer 14

To promote efficient combustion and prevent pre-ignition

Question 15

What is used to grade the quality of petrol?

Answer 15

Research octane number (RON)

Question 16

What does an alkane that burns efficiently have?

Answer 16

A high octane number

Question 17

Describe the effect if chain length on octane number

Answer 17

The longer the chain length, the lower the octane number

Question 18

Describe the effect of chain branching on octane number

Answer 18

The more branching, the higher the octane number

Question 19

Why is 2-methylpentane more volatile than hexane?

Answer 19

The branching of 2-methylpentane makes it more volatile than hexane as the branches means there is less surface contact, the van der Waals’ forces are weaker so less energy is needed to break them. This means it can turn into a gas more easily

Question 20

What does burning alkanes in a limited supply of oxygen result in?

Answer 20

Incomplete combustion

Question 21

Write an equation for the formation of NO

Answer 21

N2 + O2 > 2NO

Question 22

What is complete combustion?

Answer 22

When alkanes burn in a plentiful supply of oxygen to form carbon dioxide and water

Question 23

Write an equation for the complete combustion of hexane

Answer 23

C6H14 + 9.5 O2 > 6CO2 + 7H2O

Question 24

What is incomplete combustion?

Answer 24

When alkanes burn in a limited supply of oxygen to form carbon monoxide or soot rather than carbon dioxide

Question 25

Write an equation to show the incomplete combustion of hexane

Answer 25

C6H14 + 6.5 O2 > 6CO + 7H2O

Question 26

What is catalytic cracking?

Answer 26

When long-chain hydrocarbons are broken down into a mixture of shorter-chain alkanes and alkenes.

Question 27

Write an equation to show the cracking of decane

Answer 27

C10H22 > C8H18 + C2H4

Question 28

What contributes to global warming?

Answer 28

The absorption of infra-red radiation by gas molecules in the atmosphere

Question 29

Why are carbon dioxide and methane known as greenhouse gases?

Answer 29

They absorb heat energy to warm up the atmosphere

Question 30

What happens to the molecules when they absorb infra-red radiation?

Answer 30

The bonds vibrate and stretch when they absorb energy

Question 31

What is the ‘greenhouse effect’ of a given gas dependent on?

Answer 31

1-it’s atmospheric concentration

2-it’s ability to absorb infrared radiation

Question 32

Why are scientists more concerned about carbon dioxide as a greenhouse gas than methane?

Answer 32

Because the concentration is higher

Question 33

Why is it important to control global warming?

Answer 33

Because if not:
~rising sea level
~climate change
~loss of natural habitats 
~melting of polar ice

Question 34

Name and explain a new technology scientists are developing to minimise climate change.

Answer 34

Carbon capture and storage (CCS)
Involves the removal of waste carbon dioxide before it enters the atmosphere.
a) CO2 can be turned into liquid and injected deep in the oceans or stored geological formations.
b) waste CO2 can be reacted with metal oxides to form stable carbonate minerals.

Question 35

Explain why the incomplete combustion is potentially dangerous?

Answer 35

Because carbon monoxide binds to haemoglobin better than oxygen does so results in death.

Question 36

What information are scientists providing to change opinions?

Answer 36

They are providing scientific evidence to governments to verify that global warming is taking place.