Chapter 16.3, Problem 28SSC

Interpretation Introduction

Interpretation:

The relation between the exponents of rate equation for a chemical reaction and the coefficient in the chemical reaction needs to be explained.

Concept introduction:

The relationship between rate of a chemical reaction and concentration of reactants is expressed by rate law. Rate law is written using the concentration of reactants, each raised to a power which is experimentally determined and rate constant k.

Answer to Problem 28SSC

The coefficient of the individual reactants is raised to the concentration in the rate equation.

Explanation of Solution

The exponents of rate equation are the coefficients of the reactants in the chemical equation.

For the reaction,

${\text{N}}_{\text{2}}\text{+}3{\text{H}}_{\text{2}}\to 2{\text{NH}}_{\text{3}}$

Here, the coefficient of ${\text{N}}_{\text{2}}$ is one and the coefficient of ${\text{H}}_{\text{2}}$ is 2. So, in the rate equation, every reactant is raised to the coefficient of them. So, the rate equation is,

$\text{Rate}\text{=}k{\text{[N}}_{\text{2}}]{[{\text{H}}_{\text{2}}]}^3$

Conclusion

In the rate equation, every reactant is raised to their coefficient in the chemical equation.