IB Chemistry SL Reactivity 2.3.4 Le Châtelier's Principle

Practise predicting how an equilibrium composition responds to changes in concentration, pressure or temperature. Use gas-mole counts and reaction enthalpy to justify direction,…

Syllabus
First assessment 2025
Objective
2.3.4
Level
SL

Exam points

  • predict a concentration-change shift that consumes part of the added species
  • use gas coefficients to predict the pressure response toward fewer or more gaseous moles
  • use the endothermic direction for temperature shifts and identify when K changes

2.3.4—Le Châtelier's principle question 1

[Maximum number: 1]

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.

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