This exam focus covers Exam Focus: Alkanes within Alkanes for GCSE Chemistry. Topic 38: Alkanes It is section 10 of 12 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
🎯 Exam Focus: Alkanes
very-high Formula questions (1-2 marks): Use CₙH₂ₙ₊₂ to determine molecular formula. Must show working.
high Saturated/unsaturated distinction (2 marks): Define saturated as "only single C-C bonds" and contrast with alkenes.
high Drawing structures (2-3 marks): Draw displayed formula with each carbon making exactly 4 bonds.
Common exam question: "Explain what is meant by 'saturated'" — Answer must include "only single C-C bonds" (not just "full of hydrogen").
Edexcel 1CH0: Examined in Paper 2 (1CH0/2). Properties of alkanes and their combustion (complete and incomplete) are tested; Edexcel also covers the environmental impact of burning fossil fuels. In Edexcel-style questions, the command word "Suggest" appears frequently — use your chemistry knowledge to apply to an unfamiliar context.
Practice questions for Alkanes
What is the general formula for the alkane homologous series?
Explain why the boiling point of alkanes increases as the chain length increases.