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

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

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

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

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

Testing for the products of combustion Cobalt chloride paper Lime water

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

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

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

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

Sulphur dioxide SO2 Dissolves in rain water to produce acid rain

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?

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.

Alternative Fuels