Some cars use hydrogen as a fuel instead of petrol. The table compares hydrogen and petrol as car fuels.
| Property | Hydrogen | Petrol |
|---|---|---|
| energy released per kg / MJ | 142 | 47 |
| state at room temperature | gas | liquid |
| products of combustion in an engine | water (and some oxides of nitrogen) | carbon dioxide, water, carbon monoxide, soot and oxides of nitrogen |
| how the fuel is obtained | mainly from methane (natural gas); some by electrolysis of water | fractional distillation of crude oil |
| number of UK filling stations | about 10 | about 8000 |
Write the balanced equation for the combustion of hydrogen. Include state symbols.
A hydrogen car carries 5.0 kg of hydrogen. Calculate the mass of petrol that would release the same amount of energy.
Evaluate the use of hydrogen instead of petrol as a fuel for cars. Use the information in the table and your own knowledge.
37 exam-style questions on Edexcel GCSE Chemistry 9.1 Fuels, covering 9.1.1 Hydrocarbons and crude oil, 9.1.2 Fractional distillation of crude oil and its fractions, 9.1.3 The alkanes as a homologous series, 9.1.4 Complete and incomplete combustion, 9.1.5 Pollutants from burning fuels, 9.1.6 Hydrogen as a fuel and non-renewable fossil fuels, and 9.1.7 Cracking of larger alkanes. Each one has a worked solution and a mark scheme showing where the marks go.