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Amount of substance

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Question 15

An industrial synthesis of a pharmaceutical active ingredient involves a three-stage process:

Step 1: P→Q(85% yield) \text{Step 1: } \text{P} \rightarrow \text{Q} \quad (85\% \text{ yield}) Step 1: P→Q(85% yield) Step 2: Q→R(60% yield) \text{Step 2: } \text{Q} \rightarrow \text{R} \quad (60\% \text{ yield}) Step 2: Q→R(60% yield) Step 3: R→S(75% yield) \text{Step 3: } \text{R} \rightarrow \text{S} \quad (75\% \text{ yield}) Step 3: R→S(75% yield)

What is the overall percentage yield of the final product S\text{S}S from the starting material P\text{P}P?

A

20%20\%20%

B

38%38\%38%

C

51%51\%51%

D

73%73\%73%

Markscheme

Amount of substance Questions

  1. A Level
  2. /Chemistry
  3. /Amount of substance

79 exam-style questions on AQA A Level Chemistry Amount of substance, covering Relative atomic mass and relative molecular mass, The mole and the Avogadro constant, The ideal gas equation, Empirical and molecular formula, and Balanced equations and associated calculations. Each one has a worked solution and a mark scheme showing where the marks go.

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