Chapter 16.3, Problem 27SSC

Interpretation Introduction

Interpretation:

The reason due to which it is important to know that the reaction rate is an average rate needs to be explained.

Concept introduction:

The average rate of an action or process is defined as the change in a given quantity during a specific period of time. In equation form, the average rate is expressed as follows:

$\text{Average}\text{rate=}\frac{\Delta \text{Quantity}}{\Delta t}$

Answer to Problem 27SSC

Instantaneous rate changes time to time but average rate is constant for the reaction.

Explanation of Solution

The rate of a chemical reaction changes from start to end of a reaction. The rate of a reaction at particular instant of time during the chemical reaction is termed as instantaneous rate. The average rate is the average of instantaneous rate over a time period. As the instantaneous rate changes in a chemical reaction, it is important to specify that the reaction rate is average reaction rate not instantaneous rate. Average rate is the rate for the reaction not the rate of a particular instant of time.

Conclusion

In determining rate, average rate is preferred over instantaneous rate.