1. Intermediate 2 Chemistry Unit 2(a)
Fuels
Intermediate 2 Chemistry
Unit 2(a)

5. Enough fuel for 4 billion more years
Fuels and combustion
A fuel is “a substance which is burned to release energy”.
“Combustion” is another word for “burning”.
Burning requires oxygen (O2).
Enough fuel for 4 billion more years

6. Burning fuels
When a substance burns ALL of the different types of atom in it react with oxygen
Atoms in fuel
Products
Carbon
Carbon dioxide, carbon monoxide
Hydrogen
Hydrogen oxide (water)
Sulphur
Sulphur dioxide

7. Equations
Write word and chemical equations for the following substances burning:
Methane (CH4)
Glucose (C6H12O6)
Hydrogen (H2)
Ethanol (C2H5OH)
Carbon
*Coal (contains carbon, hydrogen and sulphur) – no need for a chemical equation here

8. Hydrocarbons
A hydrocarbon is “a substance which contains hydrogen and carbon ONLY”.
Which of the following substances are hydrocarbons?
Methane (CH4)
Glucose (C6H12O6)
Hydrogen (H2)
Ethanol (C2H6O)
Carbon

9. Testing for the products of combustion
Cobalt chloride paper
Lime water

10. Types of combustion
Look at a Bunsen burner and the different types of flame.
There are 2 types of combustion
complete and incomplete

11. Incomplete combustion
Hydrocarbon
oxygen
carbon dioxide
water +
Incomplete combustion
Hydrocarbon
oxygen
carbon monoxide
water +
carbon

12. Carbon Dioxide vs Monoxide
Chemical
Formula
Chemical Test
Other information
Carbon dioxide
CO2
Lime water turns from colourless to cloudy
We breath it out; it makes drinks fizzy; it dissolves in water producing a weak acid; it is associated with “global warming”
Carbon monoxide CO
No test
Poisonous gas, does not dissolve

13. Cars and pollution Cars burn petrol (C8H18)
Petrol sometimes contains sulphur compounds
What products of combustion will come out of the exhaust?

14. Sulphur dioxide
SO2
Dissolves in rain water to produce acid rain

16. Cars and pollution 2
Nitrogen monoxide and nitrogen dioxide also come out the exhausts of cars
They also cause acid rain
Where do they come from?

17. N2 O2 N O Nitrogen and Oxygen
A high-energy spark from the engine spark plug allows N2 and O2 to react.
Oxides of nitrogen (NO, NO2 etc) are produced.

18. Alternative Fuels