Crude Oil and Fuels

Question 1

What is a mixture?

Answer 1

A substance containing different substances that aren’t chemically bonded together.

Question 2

What is crude oil mostly a mixture of?

Answer 2

Hydrocarbons like petrol or diesel.

Question 3

Why are we able to separate the hydrocarbons in crude oil?

Answer 3

Because the different hydrocarbons aren’t chemically bonded together so they retain their individual characteristics.

Question 4

Describe fractional distillation.

Answer 4

Crude oil is heated to a gas and then enters the bottom of a fractioning column. The column has a temperature gradient running through it - it’s hottest at the bottom and gets cooler further up. The gas rises and different hydrocarbons in it condense at different temperatures. These are known as fractions and are collected.

Question 5

What is the link between the length of a hydrocarbon and its boiling point?

Answer 5

The longer the hydrocarbon, the higher its boiling point.

Question 6

What are alkanes?

Answer 6

Different length chains of carbons that are surrounded by hydrogen atoms.

Question 7

What type of bonding is present in an alkane?

Answer 7

Covalent

Question 8

What does saturated mean?

Answer 8

The atoms in a molecule have formed the most bonds they can. This means the molecule has no double bonds.

Question 9

What is the general formula for alkanes?

Answer 9

C. H

n. 2n+2

Question 10

What is the link between the length of an alkane and its viscosity?

Answer 10

The shorter the molecule, the less viscous it is.

Question 11

What is the link between the length of an alkane and its boiling point?

Answer 11

The shorter the molecule the lower its boiling point.

Question 12

What is the link between the length of an alkane and its flammability?

Answer 12

The shorter the molecule, the more flammable it is.

Question 13

How is carbon dioxide released into the atmosphere?

Answer 13

When we burn fossil fuels for energy, carbon and hydrogen are released. They mix with oxygen in the air to produce carbon dioxide and water vapour.

Question 14

What is produced when fossil fuels are burnt but there isn’t enough oxygen in the air?

Answer 14

Carbon monoxide

Question 15

What is produced when a fuel containing sulphur combusts?

Answer 15

Sulphur dioxide

Question 16

How is acid rain formed?

Answer 16

Sulphur dioxide from burning fuel mixes with clouds to form dilute sulphuric acid.

Question 17

What are the consequences of acid rain?

Answer 17

• Lakes become acidic
• Poisons wildlife
• Ruins buildings and statues

Question 18

What are two methods of reducing the amount of acid rain?

Answer 18

• Removing sulphur from fuels before burning them. This takes a lot of energy.
• Remove sulphur dioxide from waste gases using an acid gas scrubber.

Question 19

What is global dimming?

Answer 19

When soot and ash are released into the atmosphere and reflect light back into space.

Question 20

How much darker is the Earth now than it was 50 years ago?

Answer 20

Up to 25%

Question 21

Why do some scientists not believe in global dimming?

Answer 21

They believe that the evidence is due to inaccurate equipment.

Question 22

How is bioethanol produced?

Answer 22

By fermenting plants.

Question 23

What is a use of bioethanol?

Answer 23

Powering some cars.

Question 24

What are three advantages of bioethanol?

Answer 24

• It is carbon neutral
• It is renewable
• Growing plants means employment

Question 25

What are three disadvantages of bioethanol?

Answer 25

• Using bioethanol requires special engine
• Isn’t widely available
• Concerns that if more farmers grow crops for bioethanol, food prices could rise

Question 26

What is biodiesel made of?

Answer 26

Vegetable oils like rapeseed and soybean.

Question 27

What is a use of biodiesel?

Answer 27

Being mixed with diesel and then being used in a Diesel engine.

Question 28

What are three advantages of biodiesel?

Answer 28

• Carbon neutral
• Can be used in a normal engine
• Fewer particulates

Question 29

What are three disadvantages of biodiesel?

Answer 29

• Cannot replace diesel
• Very expensive
• Could increase food prices

Question 30

What are two advantages of using hydrogen gas as a fuel?

Answer 30

• Very clean

* Comes from water so won’t run out any time soon

Question 31

What are three disadvantages of using hydrogen gas as a fuel?

Answer 31

• Requires a special engine
• Isn’t widely available
• Hard to store as it is very flammable