#63
Quantitative chemistry
Paper 1 · Exam
Key steps (method)
- Write the balanced symbol equation.
- Convert what you’re given into a useful quantity (mass ↔ moles; concentration × volume; gas volume).
- Use ratios from the balanced equation.
- Apply percentage yield / atom economy / concentration formulae carefully.
Common mistakes
- Forgetting to balance before using mole ratios.
- Mixing units (cm³ vs dm³; g vs kg).
- Rearrangement errors (especially concentration and yield).
Exam-style questions (quick)
- Calculate the mass of product formed from a given mass of reactant (use moles).
- A reaction has a theoretical yield of 10.0 g but produced 7.5 g. Calculate % yield.
- Explain how changing concentration affects the mass of product in a limiting-reagent scenario.
Revision links
- FreeScienceLessons playlist: https://www.youtube.com/playlist?list=PL9IouNCPbCxUhxxFUbR4SNfwmaRB8mYX3
- PMT notes + questions: https://www.physicsandmathstutor.com/chemistry-revision/gcse-aqa/quantitative-chemistry/
- BBC Bitesize: https://www.bbc.co.uk/bitesize/topics/z87mw6f