This exam focus covers Exam Focus: Alkenes within Alkenes for GCSE Chemistry. Revise Alkenes in Organic Chemistry for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 12 of 14 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
🎯 Exam Focus: Alkenes
very-high Bromine water test (2 marks): Say "decolourised" not just "changes colour". Must state the observation AND the conclusion.
very-high Formula questions (1-2 marks): Use CₙH₂ₙ. Common trap: choosing the alkane formula CₙH₂ₙ₊₂ by mistake.
high Addition reaction equations (2 marks): Show product clearly — double bond becomes single, one atom from each reactant bonds to each carbon.
high Unsaturated definition (1-2 marks): "Contains a C=C double bond" — must be this specific, not just "reactive".
Edexcel 1CH0: Examined in Paper 2 (1CH0/2). Addition reactions of alkenes (with water, halogens, hydrogen) and the bromine water test are key Edexcel exam points. In Edexcel-style questions, the command word "Suggest" appears frequently — use your chemistry knowledge to apply to an unfamiliar context.
Practice questions for Alkenes
What is the general formula for alkenes?
Explain what is meant by the term 'unsaturated' when applied to alkenes.