This exam tips covers Exam Tips for Moles within Moles & Calculations for GCSE Chemistry. Revise Moles & Calculations in Quantitative Chemistry for GCSE Chemistry with 22 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 14 of 15 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
Topic position
Section 14 of 15
Practice
22 questions
Recall
20 flashcards
💡 Exam Tips for Moles
🎯 Common Question Types:
- Calculate Mr of a given compound (1-2 marks)
- Multi-step moles calculation using a balanced equation (3-4 marks)
- Calculate percentage yield given actual and theoretical yield (2-3 marks)
- Calculate atom economy from a balanced equation (2 marks)
- Explain why mass appears to change during a reaction (2-3 marks)
📝 Key Command Words:
- Calculate: Show all working; include units in final answer
- Explain: State the principle (conservation of mass) and apply it to the scenario
- Suggest: Give a scientific reason why yield might be less than 100%
- Show that: Work towards the given answer, showing every step
⚠️ Common Mistakes to Avoid:
- Forgetting to divide cm³ by 1000 when using concentration formulas (1 dm³ = 1000 cm³)
- Not using the mole ratio from the balanced equation (the coefficients matter!)
- Rounding too early — only round at the very final step
- Confusing atom economy with percentage yield — atom economy is theoretical, yield is experimental
- Forgetting that Mr has no units