This exam tips covers Exam Tips: 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 13 of 14 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 13 of 14
Practice
20 questions
Recall
15 flashcards
💡 Exam Tips: Alkenes
🎯 Common Question Types:
- Write the molecular formula for a named alkene (1 mark)
- Describe the bromine water test for unsaturation (2 marks)
- Write an addition reaction equation (2 marks)
- Explain what unsaturated means (1-2 marks)
📝 Key Command Words:
- Describe: State the observation (colour change) and conclusion
- Explain: Link to C=C double bond and addition reaction
- Write: Show the double bond opening in the equation
⚠️ Common Mistakes to Avoid:
- Using CₙH₂ₙ₊₂ (alkane formula) for alkenes
- Saying bromine water "changes colour" — say "decolourised"
- Defining unsaturated as "reactive" — must say "C=C double bond"
Quick Check: What is the molecular formula of propene?
Using CₙH₂ₙ with n=3: H = 2×3 = 6. Formula = C₃H₆.
Quick Check: Write the equation for the reaction of propene with bromine water.
C₃H₆ + Br₂ → C₃H₆Br₂. Propene reacts with bromine in an addition reaction across the C=C double bond, producing 1,2-dibromopropane. The orange bromine water is decolourised.
Keep building this topic
Read this section alongside the surrounding pages in Alkenes. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Alkenes
What is the general formula for alkenes?
Explain what is meant by the term 'unsaturated' when applied to alkenes.
Quick Recall Flashcards
20 questions on Alkenes — practise free
Instant marking, adaptive difficulty, and 15 spaced repetition flashcards. Free until your GCSEs.
Try PrepWise Free