Chapter 16, Problem 1STP

Interpretation Introduction

Interpretation:

The option which is not rate of a chemical reaction needs to be identified.

Concept introduction:

Rate of a reaction is the change in the amount of products or reactants per unit time.

$\text{Rate}=\frac{-\text{Change}\text{in}\text{reactants}}{\text{Change}\text{in}\text{time}}$

Answer to Problem 1STP

D. the amount of product formed in a certain period of time.

Explanation of Solution

D. The amount of product formed in a certain period of time.

Rate of reaction does not define how much product if formed in a certain time. Rate of a reaction is the change in concentration over a period of time. It is the speed at which product is formed. Thus the option is D.

Conclusion

The correct options are as follows:

1. The speed at which a reaction takes place.

Average rate is the concentration of reactant over a period of time.

$\text{Average}\text{reaction}\text{rate}=\frac{-\Delta \left[\text{reactants}\right]}{\Delta \text{t}}$

2. The change in concentration of a reactant per unit time.

Negative sign out in front line which corrects for decreases in concentration of reactant to yield a +ve average reaction rate.

3. The change in concentration of a product per unit time.

Reaction rate can also define amount of product.

$\text{Average}\text{reaction}\text{rate}=\frac{\Delta \left[\text{products}\right]}{\Delta \text{t}}$

Change in product concentration is positive. Rate of reaction can also define in terms of change in concentration of the product per unit time.