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Topic 8: Fuels and Earth science

3 dot points across 3 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

What is crude oil, how is it separated into fuels, and how does cracking help?

Hydrocarbons and fuels: crude oil and the alkanes, fractional distillation into useful fractions, the trends in the properties of the fractions, complete combustion, and cracking.
A focused answer to Edexcel GCSE Chemistry topic 8, covering crude oil as a mixture of hydrocarbons, the alkane homologous series, how fractional distillation separates crude oil into fractions, the trends in boiling point, viscosity and flammability, complete combustion, and cracking to make more useful smaller molecules and alkenes.
10 min answer →

What pollutants are produced when fuels burn, and what problems do they cause?

Pollution from fuels: incomplete combustion and carbon monoxide and soot, sulfur dioxide and oxides of nitrogen, acid rain, and the advantages and disadvantages of hydrogen as a fuel.
A focused answer to Edexcel GCSE Chemistry topic 8, covering incomplete combustion and the production of carbon monoxide and soot, the formation of sulfur dioxide and oxides of nitrogen, the problems these pollutants cause including acid rain, and the advantages and disadvantages of using hydrogen as a fuel.
9 min answer →

How did the Earth's atmosphere evolve, and how do greenhouse gases affect the climate?

The Earth and atmosphere: the evolution of the atmosphere from volcanic gases to the present composition, the role of photosynthesis, the greenhouse effect, and human activities affecting greenhouse gas levels.
A focused answer to Edexcel GCSE Chemistry topic 8, covering how the Earth's early atmosphere formed from volcanic activity, how photosynthesis increased oxygen and reduced carbon dioxide, the present composition of the atmosphere, the greenhouse effect and the main greenhouse gases, and the human activities that increase greenhouse gas levels and affect the climate.
9 min answer →