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IB Chemistry SL 2.3.4 Le Ch Teliers Principle Questions

Use real SL exam questions to predict equilibrium shifts and composition changes after concentration, temperature and pressure changes.

Syllabus
First assessment 2025
Course
Chemistry SL
Level
SL

Exam points

  • Predict the direction of equilibrium shift after changing a reactant/product concentration and explain the resulting composition or yield.
  • Deduce how an exothermic or endothermic equilibrium responds to a temperature change, including the effect on Kc.
  • Predict how pressure, volume, water, solids or a catalyst affect equilibrium composition, yield and the value of Kc.

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Study 2.3.4—Le Châtelier's principle conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

IB Chemistry SL 2.3.4 Le Ch Teliers Principle Questions question 1

[Maximum number: 3]

Question (a)

(a)

State and explain the effect of a catalyst on the position of equilibrium.

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Question (b)

(b)

Ethanoic acid reacts with ethanol to form the ester ethyl ethanoate.

CH3COOH(l)+CH3CH2OH(l)⇌H+CH3COOCH2CH3(l)+H2O(l)\mathrm{CH}_{3} \mathrm{COOH}(\mathrm{l})+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}(\mathrm{l}) \stackrel{\mathrm{H}^{+}}{\rightleftharpoons} \mathrm{CH}_{3} \mathrm{COOCH}_{2} \mathrm{CH}_{3}(\mathrm{l})+\mathrm{H}_{2} \mathrm{O}(\mathrm{l})

The esterification reaction is exothermic. State the effect of increasing temperature on the value of the equilibrium constant ( KcK_{\mathrm{c}} ) for this reaction.

[ 1 ]
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