Skip to content
MathsGenie logo
Open app

Course home

  1. A Level
  3. Chemistry OCR A
  5. Question bank

Physical chemistry

EasyMediumHard
12345678910111213141516171819202122232425262728293031323334353637383940414243444546
Question 8

A student investigates the esterification reaction between ethanoic acid, CH3COOH(l)\text{CH}_3\text{COOH}(\text{l})CH3​COOH(l), and ethanol, C2H5OH(l)\text{C}_2\text{H}_5\text{OH}(\text{l})C2​H5​OH(l), in the presence of an acid catalyst to produce ethyl ethanoate and water:

CH3COOH(l)+C2H5OH(l)⇌CH3COOC2H5(l)+H2O(l) \text{CH}_3\text{COOH}(\text{l}) + \text{C}_2\text{H}_5\text{OH}(\text{l}) \rightleftharpoons \text{CH}_3\text{COOC}_2\text{H}_5(\text{l}) + \text{H}_2\text{O}(\text{l}) CH3​COOH(l)+C2​H5​OH(l)⇌CH3​COOC2​H5​(l)+H2​O(l)
a.

Explain why performing the kinetic study with a large excess of ethanol allows the order of reaction with respect to ethanoic acid to be determined directly.

[2]
b.

In a separate experiment to determine the equilibrium constant, KcK_cKc​, the student mixes 13.8 g13.8\text{ g}13.8 g of ethanol (C2H5OH\text{C}_2\text{H}_5\text{OH}C2​H5​OH) with 15.0 g15.0\text{ g}15.0 g of ethanoic acid (CH3COOH\text{CH}_3\text{COOH}CH3​COOH) and adds a small amount of acid catalyst.

When the mixture reaches equilibrium at constant temperature, 0.050 mol0.050\text{ mol}0.050 mol of CH3COOH\text{CH}_3\text{COOH}CH3​COOH remains.

Calculate the value of KcK_cKc​ for this equilibrium.

[5]

Physical chemistry Questions

  1. A Level
  2. /Chemistry
  3. /Physical chemistry