OCR A Level Chemistry A
OCR A Level Chemistry A Amount of Substance Exam Questions
Free OCR A Level Chemistry A exam questions on Amount of Substance, with mark schemes. Covers the mole, molar mass, gas volumes, concentration, empirical formulae, percentage yield and atom economy.
Amount of Substance exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
StemUp mark scheme flashcards
OCR A Level Chemistry A H432 Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About OCR A Level Chemistry A Amount of Substance
This topic covers quantitative chemistry.
What you need to know
- The mole n = m/M and Avogadro's constant.
- Gases pV = nRT and 24.0 dm³ at RTP.
- Solutions n = cV and titration calculations.
- Yield and atom economy Efficiency of reactions.
Common mistakes in Amount of Substance
- Not converting cm³ to dm³.
- Using wrong units in pV = nRT.
- Confusing yield and atom economy.
Try three Amount of Substance exam-style questions
1. Find the moles in 25.0 cm³ of 0.100 mol dm⁻³ HCl. (1 mark)
Show the mark scheme answer
2.50 x 10⁻³ mol.
2. Calculate the empirical formula from C 85.7% and H 14.3%. (2 marks)
Show the mark scheme answer
Ratio 7.14 : 14.3 (1) gives CH₂ (1).
3. Define atom economy. (1 mark)
Show the mark scheme answer
Mass of desired product over total mass of products x 100.
Amount of Substance FAQs
What does this topic cover?
The mole, gas volumes, solutions and yields.
Which practical links here?
Acid-base titration and determining water of crystallisation.
What units go in pV = nRT?
Pa, m³ and K.
Revise this topic with flashcards: OCR A Level Chemistry A H432 Flashcards, with mark scheme answers for Anki and Quizlet.
