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

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Question 19
1.

P\text{P}P and Q\text{Q}Q react together to form an equilibrium mixture.

P(aq)+2Q(aq)⇌R(aq) \text{P}(aq) + 2\text{Q}(aq) \rightleftharpoons \text{R}(aq) P(aq)+2Q(aq)⇌R(aq)

An aqueous solution containing 0.40 mol0.40\text{ mol}0.40 mol of P\text{P}P is added to an aqueous solution containing 0.40 mol0.40\text{ mol}0.40 mol of Q\text{Q}Q.

When equilibrium is reached, the mixture contains 0.035 mol0.035\text{ mol}0.035 mol of R\text{R}R.

Calculate the amount of P\text{P}P and the amount of Q\text{Q}Q, in moles, in the equilibrium mixture.

[3]
2.

At a different temperature, another equilibrium mixture contains 0.50 mol0.50\text{ mol}0.50 mol of P\text{P}P, 0.35 mol0.35\text{ mol}0.35 mol of Q\text{Q}Q and 0.045 mol0.045\text{ mol}0.045 mol of R\text{R}R in 250 cm3250\text{ cm}^3250 cm3 of solution.

Calculate the value of the equilibrium constant KcK_cKc​ and deduce its units.

[5]

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

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