Frequency: Very high — 60+ raw hits across OCR J248 Jun 2022–2024 corpus. Chemical equations appear embedded throughout all chemistry papers. This is a P1 topic (weight 41.0 in OCR ranking).
Typical question types:
- "Balance this equation" — 1–2 marks (most common format)
- "Write a balanced symbol equation for..." — 2–3 marks
- "Explain why the mass appears to decrease/increase" — 2–3 marks
- "Write the formula of..." using ionic charges — 1 mark
- "Add state symbols to this equation" — 1 mark
- "Use the equation to calculate the mass of X produced" — 2–3 marks (links to moles topic)
OCR J248 specific: Conservation of mass frequently appears in the context of practical experiments — expect questions about a student monitoring a reaction on a balance and explaining unexpected mass readings.
AQA 8462 specific: Balancing is tested in Paper 1 (unit 3, Chemical Changes context) and conservation of mass links directly to the quantitative chemistry unit.
Edexcel 1CH0: Examined in Paper 1 (1CH0/1). Formulae, equations, and conservation of mass underpin the entire paper — balancing equations and writing formulae using ionic charges appear in multiple questions. In Edexcel-style questions, the command word "Suggest" appears frequently — use your chemistry knowledge to apply to an unfamiliar context.
This exam focus covers Exam Connection within Formulae, Equations and Conservation of Mass for GCSE Chemistry. Revise Formulae, Equations and Conservation of Mass in Quantitative Chemistry for GCSE Chemistry with 13 exam-style questions and 12 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. 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.
Practice questions for Formulae, Equations and Conservation of Mass
Which of the following is the correct formula for oxygen gas?
Explain why mass is conserved in a chemical reaction.