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IB Chemistry HL 1.4.1 Entropy (S) Question Bank

Practise IB Chemistry HL 1.4.1 by applying entropy (s) to exam-style questions.

Syllabus
First assessment 2025
Course
Chemistry HL
Level
HL

Exam points

  • identify the relevant chemical structure, process or evidence
  • apply the correct chemical model or equation
  • evaluate the result using chemical reasoning and data

1.4.1 (HL)—Entropy (S) question 1

[Maximum number: 1]

Nitrous acid, HNO2\mathrm{HNO}_{2}, is a weak acid which can be used to make acidic buffers.

The overall reaction for the synthesis of ethyl ethanoate from ethane is:

2C2H6( g)+Cl2( g)+32O2( g)→C4H8O2( g)+2HCl( g)+H2O( g)2 \mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g})+\frac{3}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}_{2}(\mathrm{~g})+2 \mathrm{HCl}(\mathrm{~g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{~g})

Calculate the standard entropy change, ΔSθr\Delta S^{\theta}{ }_{r}, in JK−1 mol−1\mathrm{JK}^{-1} \mathrm{~mol}^{-1}, for this reaction. Use section 13 of the data booklet and Sθ\mathrm{S}^{\theta} of ethyl ethanoate =259JK−1 mol−1=259 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}.

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