IB Chemistry SL Reactivity 2.1.2 Mole Ratios

Practise extracting reacting ratios from a balanced equation and applying them to mass, solution, gas or equilibrium quantities. Convert the starting information to moles,…

Syllabus
First assessment 2025
Objective
2.1.2
Level
SL

Exam points

  • convert mass, concentration-volume or gas data into amount before using a ratio
  • multiply by the target-to-source coefficient ratio from the balanced equation
  • convert the resulting amount into the requested mass, volume or concentration

2.1.2—Mole ratio question 1

[Maximum number: 2]

The reaction between ethanoic acid and ethanol is homogeneous and reversible.

C2H6O(l)+C2H4O2(l)⇌C4H8O2(l)+H2O(l)ΔHθr=−4 kJ mol−1\mathrm{C}_{2} \mathrm{H}_{6} \mathrm{O}(\mathrm{l})+\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{O}_{2}(\mathrm{l}) \rightleftharpoons \mathrm{C}_{4} \mathrm{H}_{8} \mathrm{O}_{2}(\mathrm{l})+\mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \quad \Delta H^{\theta}{ }_{\mathrm{r}}=-4 \mathrm{~kJ} \mathrm{~mol}^{-1}

0.6\quad 0.6 moles each of ethanol and ethanoic acid at 60∘C60^{\circ} \mathrm{C} reacted in the presence of an acid catalyst. The volume remained constant. At equilibrium 0.2 moles of ethanoic acid remained in the reaction mixture.

Calculate the amounts, in mol, of ethanol, ethyl ethanoate and water at equilibrium.

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