CAIE A-Level Chemistry AS 7.1.7 The Kc and Kp Expressions to Carry Out Questions

Practise using Kc and Kp expressions to calculate equilibrium constants, concentrations, mole fractions and partial pressures with CAIE 9701 AS questions.

Exam points

Use Kc and Kp expressions to calculate equilibrium constants and related equilibrium quantities.

[Maximum number: 1]

An alcohol, ROH, reacts reversibly with ethanoic acid to produce an ester.

\mathrm{ROH}(\mathrm{I})+\mathrm{CH}_{3} \mathrm{COOH}(\mathrm{I}) \rightleftharpoons \mathrm{CH}_{3} \mathrm{COOR}(\mathrm{I})+\mathrm{H}_{2} \mathrm{O}(\mathrm{I})

3.0 mol of $\mathrm{ROH}, 2.0 \mathrm{~mol}$ of ethanoic acid and 1.0 mol of water are mixed together. At equilibrium, 1.5 mol of $\mathrm{CH}_{3} \mathrm{COOR}$ is present.

What is the value of the equilibrium constant, $K_{\mathrm{c}}$ , for this reaction?

0.20

0.25

2.00

5.00

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CAIE A-Level Chemistry AS 7.1.7 The Kc and Kp Expressions to Carry Out Questions question 1