Chapter 14, Problem 42PS

(a)

Interpretation Introduction

Interpretation:

From the given energy profile diagram the type of reaction as either exothermic or endothermic has to be explained.

Concept introduction:

In order to establish the plausibility of a mechanism, one must compare the rate law of the rate determining step to the experimentally determined rate law.

Energy profile diagram: It is diagrammatic representation of the reaction pathway which is depicted along the reaction coordinates that is energy and time as the reactions proceeds in product formation.

Rate determining step: In a chemical reaction the rate determining step is the slowest step in which the rate of the reaction depends on the rate of that slowest step.

Rate law: It is generally the rate equation that consists of the reaction rate with the concentration or the pressures of the reactants and constant parameters.

Activation energy: It is defined as the minimum energy required by the reacting species in order to undergo chemical reaction.

Intermediate species: It is the species formed during the middle of the chemical reaction between the reactant and the desired product.

Exothermic reaction: The reaction is termed as exothermic reaction if energy is released in the form of heat from the reaction system to the surroundings.

Endothermic reaction: The reaction is termed as endothermic reaction when energy is absorbed from the surroundings in order to accomplish the reaction.

Arrhenius equation:

• Arrhenius equation is a formula that represents the temperature dependence of reaction rates
• The Arrhenius equation has to be represented as follows

  $\begin{array}{l}k=A{e}^{-E_a/RT}\\ \ln k=\ln A{e}^{-E_a/RT}\\ \ln k=\left(-\frac{{\text{E}}_{\text{a}}}{\text{R}}\right)\left(\frac{1}{\text{T}}\right)+\ln \text{A}\end{array}$

• $E_a$ represents the activation energy and it’s unit is $\text{kJ/mol}$
• R represents the universal gas constant and it has the value of 8.314 $\text{J/K}\text{.mol}$
• T represents the absolute temperature
• A represents the frequency factor or collision frequency
• e represents the base of natural logarithm
•  Arrhenius equation equation was proposed by Svante Arrhenius in 1889.

(b)

Interpretation Introduction

Interpretation:

From the given energy profile diagram, the reaction occur in more than one step has to be predicted.

Concept introduction:

In order to establish the plausibility of a mechanism, one must compare the rate law of the rate determining step to the experimentally determined rate law.

Energy profile diagram: It is diagrammatic representation of the reaction pathway which is depicted along the reaction coordinates that is energy and time as the reactions proceeds in product formation.

Rate determining step: In a chemical reaction the rate determining step is the slowest step in which the rate of the reaction depends on the rate of that slowest step.

Rate law: It is generally the rate equation that consists of the reaction rate with the concentration or the pressures of the reactants and constant parameters.

Activation energy: It is defined as the minimum energy required by the reacting species in order to undergo chemical reaction.

Intermediate species: It is the species formed during the middle of the chemical reaction between the reactant and the desired product.

Exothermic reaction: The reaction is termed as exothermic reaction if energy is released in the form of heat from the reaction system to the surroundings.

Endothermic reaction: The reaction is termed as endothermic reaction when energy is absorbed from the surroundings in order to accomplish the reaction.

Arrhenius equation:

• Arrhenius equation is a formula that represents the temperature dependence of reaction rates
• The Arrhenius equation has to be represented as follows

  $\begin{array}{l}k=A{e}^{-E_a/RT}\\ \ln k=\ln A{e}^{-E_a/RT}\\ \ln k=\left(-\frac{{\text{E}}_{\text{a}}}{\text{R}}\right)\left(\frac{1}{\text{T}}\right)+\ln \text{A}\end{array}$

• $E_a$ represents the activation energy and it’s unit is $\text{kJ/mol}$
• R represents the universal gas constant and it has the value of 8.314 $\text{J/K}\text{.mol}$
• T represents the absolute temperature
• A represents the frequency factor or collision frequency
• e represents the base of natural logarithm
•  Arrhenius equation equation was proposed by Svante Arrhenius in 1889.