This exam tips covers Exam Tips: Alcohols within Alcohols for GCSE Chemistry. Revise Alcohols in Organic Chemistry for GCSE Chemistry with 22 exam-style questions and 15 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 12 of 13 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
💡 Exam Tips: Alcohols
🎯 Common Question Types:
- Write the fermentation equation for ethanol (2 marks)
- Compare fermentation and hydration of ethene (4 marks)
- State the functional group of alcohols (1 mark)
- Explain why ethanol dissolves in water (2 marks)
📝 Key Command Words:
- Write: Balanced equation with CO₂ product for fermentation
- Compare: State difference for each aspect (not just describe one)
- Explain: The -OH group forming strong attractions with water molecules for solubility
⚠️ Common Mistakes to Avoid:
- Forgetting CO₂ in the fermentation equation
- Saying fermentation requires oxygen (it's anaerobic)
- Writing the functional group as "OH" without the dash (-OH)
Quick Check: Write the word equation and symbol equation for the fermentation of glucose.
Word equation: glucose → ethanol + carbon dioxide (using yeast enzymes, anaerobic, 25-35°C). Symbol equation: C₆H₁₂O₆(aq) → 2C₂H₅OH(aq) + 2CO₂(g).
Quick Check: Give one advantage and one disadvantage of producing ethanol by fermentation compared to hydration of ethene.
Advantage: Fermentation uses renewable resources (plant sugars), so it is more sustainable and approximately carbon neutral. Disadvantage: Fermentation is much slower than hydration of ethene and produces impure ethanol that requires distillation.
Practice questions for Alcohols
What is the functional group present in all alcohols?
Explain what happens when ethanol reacts with sodium metal. Include a balanced equation in your answer.