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Combustion of hydrocarbons for Edexcel GCSE Chemistry

Combustion of hydrocarbons

This page covers the following topics:

1. Products and energy
2. Equations
3. Calculating energy change

Combustion is the burning of a fuel in oxygen. The products of combustion depend on oxygen supply to the fuel and whether the fuel contained any impurities. When there is incomplete combustion there is insufficient oxygen to convert the fuel fully into carbon dioxide.

Products and energy

When combusting hydrocarbons the equation will depend on whether the oxygen supply was sufficient, remember to check the balancing numbers to determine what the products will be.

Equations

The energy given out by the combustion of a hydrocarbon can be calculated using the equation shown.

Calculating energy change

1

What are the values of X and Y?

Cโ‚„Hโ‚โ‚€ + XOโ‚‚ โ†’ 4COโ‚‚ + YHโ‚‚O

X = 13/2 and Y = 5

What are the values of X and Y?

Cโ‚„Hโ‚โ‚€ + XOโ‚‚ โ†’ 4COโ‚‚ + YHโ‚‚O

2

What is the definition of combustion?

the burning of a fuel in oxygen

What is the definition of combustion?

3

A spirit burner weighs 7.6 g before and 6.7 g after being used to heat 50 ml of water from 20 ยบC to 30 ยบC. How much energy is given out by this fuel?

2090 J

A spirit burner weighs 7.6 g before and 6.7 g after being used to heat 50 ml of water from 20 ยบC to 30 ยบC. How much energy is given out by this fuel?

4

Write an equation to show incomplete combustion of propene, where 4 molecules of oxygen have been used.

Cโ‚ƒHโ‚† + 4Oโ‚‚ โ†’ 2COโ‚‚ + 3Hโ‚‚O + CO

Write an equation to show incomplete combustion of propene, where 4 molecules of oxygen have been used.

5

Complete this sentence, butane burned fully in oxygen formsโ€ฆ

carbon dioxide and water

Complete this sentence, butane burned fully in oxygen formsโ€ฆ

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