Chapter 17, Problem 74A

Interpretation Introduction

Interpretation:

The effect of the raise in temperature in the equilibrium of combustion reaction of methane has to be explained.

Concept Introduction:

Le Chatelier's principle states that when there is change in temperature, pressure or concentration of reactants or products in an equilibrium reaction, the equilibrium shifts in such a way as to nullify the effect.

Answer to Problem 74A

The combustion of methane occurs in a Bunsen burner. When the reaction is in an equilibrium, the increase in temperature to the system shifts the equilibrium in the direction that reduce the effect of temperature. The equilibrium position is shifted to the left side and so the concentration of the reactants increase. Thus the value for K decreases.

So the answer is option b.

Explanation of Solution

  $\begin{array}{l}C{H}_4(g)+2O_2(g)\rightleftharpoons C{O}_2(g)+2H_{2}O(g)\\ \mathrm{Equilibrium}ConstantK=\frac{[C{O}_2]{[H_{2}O]}^2}{[C{H}_4]{[O_2]}^2}\end{array}$

When in a system at equilibrium change in concentration, temperature and pressure takes place, the equilibrium shifts in the direction to reduce the change. The combustion of methane occurs in a Bunsen burner. When the reaction is in equilibrium, the increase in temperature to the system shifts the equilibrium in the direction that reduces the effect of temperature. The equilibrium position will shift to the left side thus, the concentration of the reactants increases and the value for K decreases.