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Atoms and reactions

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Question 80

A student preparing aspirin (C9H8O4\text{C}_9\text{H}_8\text{O}_4C9​H8​O4​) reacts 6.90 g of salicylic acid (C7H6O3\text{C}_7\text{H}_6\text{O}_3C7​H6​O3​) with excess ethanoic anhydride according to the equation:

C7H6O3+C4H6O3→C9H8O4+CH3COOH \text{C}_7\text{H}_6\text{O}_3 + \text{C}_4\text{H}_6\text{O}_3 \rightarrow \text{C}_9\text{H}_8\text{O}_4 + \text{CH}_3\text{COOH} C7​H6​O3​+C4​H6​O3​→C9​H8​O4​+CH3​COOH Mr(C7H6O3)=138.0Mr(C9H8O4)=180.0 M_r(\text{C}_7\text{H}_6\text{O}_3) = 138.0 \qquad M_r(\text{C}_9\text{H}_8\text{O}_4) = 180.0 Mr​(C7​H6​O3​)=138.0Mr​(C9​H8​O4​)=180.0

The reaction produces 6.12 g of purified aspirin.

What is the percentage yield of aspirin?

A

52.152.152.1

B

68.068.068.0

C

76.776.776.7

D

88.788.788.7

Markscheme

Atoms and reactions Questions

  1. A Level
  2. /Chemistry
  3. /Atoms and reactions

199 exam-style questions on OCR A A Level Chemistry Atoms and reactions, covering Atomic structure and isotopes, Compounds, formulae and equations, Amount of substance, Acids, and Redox. Each one has a worked solution and a mark scheme showing where the marks go.

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