Chapter 18.4, Problem 1RC

(a)

Interpretation Introduction

Interpretation:

The correct balanced equation has to be written.

Concept Introduction:

Chemical equation is the representation of a chemical reaction, in which the reactants and products of the reactions are represented left and right side of an arrow respectively by using their respective chemical formulas.

Balanced chemical equation of a reaction is written according to law of conservation of mass.

Stoichiometry of a chemical reaction is the relation between reactants and products of the reaction and it is represented by the coefficients used for the reactants and products involved in the chemical equation.

(b)

Interpretation Introduction

Interpretation:

The correct balanced equation and the change in entropy for the given reaction have to be found.

Concept Introduction:

Entropy is the measure of randomness in the system. The entropy change in a reaction is the difference in entropy of the products and reactants.${\text{(ΔS}}_{\text{rxn}}\text{)}$ can be calculated by the following equation.

${\text{ΔS}}_{\text{rxn}}{\text{ = S}}_{\text{Products}}-{\text{ S}}_{\text{reactants}}$

Where,

  ${\text{S}}_{\text{reactants}}$ is the entropy of the reactants

  ${\text{S}}_{\text{Products}}$ is the standard of the products

Standard entropy change in a reaction and entropy change in the system are same.

Using the value for the change in enthalpy in a system and the temperature, we can calculate ${\text{ΔS}}_{\text{surr}}$ for an isothermal reaction.

${\text{ΔS}}_{\text{surr}}\text{=-}\frac{{\text{ΔΗ}}_{\text{sys}}}{\text{T}}$

The summation of ${\text{ΔS}}_{\text{sys}}$ and ${\text{ΔS}}_{\text{surr}}$ will give the value for the entropy change in the universe ${\text{(ΔS}}_{\text{univ}})$. If the ${\text{ΔS}}_{\text{univ}}$ is positive then the reaction will be spontaneous.  If the ${\text{ΔS}}_{\text{univ}}$ is negative, then the reaction is non-spontaneous.

Chemical equation is the representation of a chemical reaction, in which the reactants and products of the reactions are represented left and right side of an arrow respectively by using their respective chemical formulas.

Balanced chemical equation of a reaction is written according to law of conservation of mass.

Stoichiometry of a chemical reaction is the relation between reactants and products of the reaction and it is represented by the coefficients used for the reactants and products involved in the chemical equation.