Using Carbon Fuels

Question 1

What are fuels used for?

Answer 1

Cooking, heating and transport.

Question 2

How do fuels burn?

Answer 2

Oxygen is required for fuel to burn.
Hydrocarbon fuel + oxygen = carbon dioxide + water . (Complete combustion)
Gases are given off when a fuel burns - Water is given off as steam and carbon dioxide.

Question 3

What is incomplete combustion?

Answer 3

There is not enough oxygen for fuel to burn completely.
The fuel gives off unwanted gases and soot and less energy is released.

Fuel + oxygen = carbon monoxide + water
Carbon monoxide is poisonous but cannot be smelt.
Heaters need to be checked regularly to make sure they are safe.

Or

Fuel + oxygen = carbon + water

Question 4

What are the characteristics of petrol?

Answer 4

1. To be able to flow
2. To burn instantly
3. Release a lot of energy
4. Cause minimal pollution- carbon dioxide and carbon monoxide
5. Little acid fumes produced
6. High cost
7. Volatile liquid - needs to be stored safely.

Question 5

What are the characteristics of coal as a fuel?

Answer 5

1. High energy value
2. Good availability
3. Bulky and dirty but easier to store but non volatile
4. High cost
5. Produces acid fumes
6. Pollution - acid rain, carbon dioxide and soot
7. Slow to ignite and burn.

Question 6

How do you test for carbon dioxide?

Answer 6

It turns limewater milky

Question 7

How do you test for water?

Answer 7

Cobalt chloride paper changes colour when water or steam touch it.

Question 8

What are the factors to consider when choosing a fuel?

Answer 8

1. Energy value
2. Ease of use
3. Cost
4. Pollution caused
5. Availability
6. Method of storage
7. Toxicity

Question 9

Complete and incomplete combustion with Bunsen burners.

Answer 9

Complete combustion when the hole is fully open - plenty of oxygen.
The flame is blue and transfers lots of energy.

The flame is yellow if the hole is partially closed - incomplete combustion. Less energy is given off and carbon monoxide and soot are produced as well as carbon dioxide and water.

Question 10

What pollution problems are created by burning fuels?

Answer 10

Carbon dioxide - global warming by destroying the ozone layer around the earth.

Carbon monoxide is poisonous.

Fuels also contain other substances - coal contains sulphur which dissolves in rainwater to make acid rain which destroys stone buildings and kills animals and plants.