Chapter 17, Problem 18A

Interpretation Introduction

Interpretation: The statement for equilibrium constant needs to be explained.

Concept Introduction: For a balanced chemical reaction,

  $aA+bB\rightleftharpoons cC+dD$

The equilibrium expression is ratio of the concentration of the products to the concentration of the reaction. The concentration of each reactant/product is raised to a power corresponding to their coefficient in the balanced equation.

The law of chemical equilibrium is given by the equilibrium expression,

  $K=\frac{{\left[C\right]}^c{\left[D\right]}^d}{{\left[A\right]}^a{\left[B\right]}^b}$

The equilibrium constant is represented as $K.$

Answer to Problem 18A

The ratio of products to reactants would always remain the same. However, the concentrations to which the reaction starts with could vary all the way to infinity. The ratio would be kept constant.

Explanation of Solution

For a balanced chemical reaction,

  $aA+bB\rightleftharpoons cC+dD$

Where,

• $A,B,C,D$ are chemical species.
• $a,b,c$ and $d$ are coefficients in the balanced equation.

The equilibrium expression is given as,

  $K=\frac{{\left[C\right]}^c{\left[D\right]}^d}{{\left[A\right]}^a{\left[B\right]}^b}$

Where,

  $K$ is the value of equilibrium constant.

Equilibrium constant is the ratio of concentration of products to the concentration of reactants at equilibrium. The position of the equilibria depends on the initial concentration, but the equilibrium constant does not depend on the initial concentration.

Based on the initial concentration of reactants, at equilibrium, there would be different concentrations of reactant and products but the ratio is constant for a specific reaction at a given specific temperature. Hence, there is only one value of the equilibrium constant for a particular system at a particular temperature but there is infinite number of equilibrium positions.