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Chemical equilibria, Le Chatelier’s principle and $K_c$

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Question 1
1.

1 mol of a diester with molecular formula C6H10O4\text{C}_6\text{H}_{10}\text{O}_4C6​H10​O4​ is added to 1 mol of water in the presence of a small amount of acid catalyst. The mixture is left to reach equilibrium at a constant temperature:

C6H10O4(l)+2H2O(l)⇌2HCOOH(l)+HO(CH2)4OH(l) \text{C}_6\text{H}_{10}\text{O}_4(\text{l}) + 2\text{H}_2\text{O}(\text{l}) \rightleftharpoons 2\text{HCOOH}(\text{l}) + \text{HO}(\text{CH}_2)_4\text{OH}(\text{l}) C6​H10​O4​(l)+2H2​O(l)⇌2HCOOH(l)+HO(CH2​)4​OH(l)

At equilibrium, xxx mol of methanoic acid are present in the mixture. Complete the details of the equilibrium mixture by finding the equilibrium amounts, in terms of xxx, of:

  • Diester
  • Water
  • Diol
[3]
2.

Deduce the structure of the diester C6H10O4\text{C}_6\text{H}_{10}\text{O}_4C6​H10​O4​ used in this reaction.

[1]
3.

A new equilibrium mixture of the same substances is prepared at a different temperature.

C6H10O4(l)+2H2O(l)⇌2HCOOH(l)+HO(CH2)4OH(l) \text{C}_6\text{H}_{10}\text{O}_4(\text{l}) + 2\text{H}_2\text{O}(\text{l}) \rightleftharpoons 2\text{HCOOH}(\text{l}) + \text{HO}(\text{CH}_2)_4\text{OH}(\text{l}) C6​H10​O4​(l)+2H2​O(l)⇌2HCOOH(l)+HO(CH2​)4​OH(l)

At equilibrium, this mixture contains:

  • 0.850 mol0.850\text{ mol}0.850 mol of diester
  • 0.360 mol0.360\text{ mol}0.360 mol of methanoic acid
  • 0.220 mol0.220\text{ mol}0.220 mol of diol

The value of the equilibrium constant, KcK_cKc​, is 0.1340.1340.134 at this temperature. Calculate the amount of water, in mol, in this new equilibrium mixture.

[4]

Chemical equilibria, Le Chatelier’s principle and $K_c$ Questions

  1. A Level
  2. /Chemistry
  3. /Chemical equilibria, Le Chatelier’s principle and $K_c$