Chapter 7, Problem 7.73CP

(a)

Interpretation Introduction

Interpretation:

The balanced equation for the reaction of ammonia in presence of air is to be determined.

Concept Introduction:

Reactant: In a chemical reaction the species that present left is denoted as reactant which undergoes chemical change and result to given new species called product.

Product: In a chemical reaction the species that present in right side is denoted as product that results from the reactant.

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.

(b)

Interpretation Introduction

Interpretation:

The equilibrium equation for the following reaction of ammonia in presence of air is to be determined.

Concept Introduction:

Equilibrium constant is explains the relationship among reactant and product at equilibrium for a particular reaction.

The equilibrium constant expression is expressed by the formula,

$\text{K=}\frac{\text{Concentration}\text{of}\text{products}}{\text{Concentration}\text{of}\text{reactants}}$

It is the ratio of concentration of product raised to power of their corresponding coefficient of stoichiometry and concentration of reactant raised to power of their corresponding coefficient of stoichiometry at equilibrium.

(c)

Interpretation Introduction

Interpretation:

The effect on the equilibrium of each given changes in the reaction of ammonia in presence of air is to be determined.

Concept Introduction:

Enthalpy $\left(H\right)$: It is the total amount of heat in a particular system.

If the value obtained for $\text{ΔH}$ in a reaction is positive then it is an endothermic reaction whereas the value obtained for $\text{ΔH}$ is negative it is an exothermic reaction.

Le Chatelier’s principle: If an equilibrium is disturbed by changing conditions, the system will moves the equilibrium to reverse the change.

Factor’s that effect chemical equilibria:

• Concentration – Equilibrium will be affected by changing the concentration of reactant or product. If we increase the concentration of reactant system will try to reverse the change by favouring forward reaction and thus increase the concentration of products. Likewise adding products increase yield of reactants.
• Temperature – When the temperature increases equilibrium will shift in the endothermic direction, in the direction that absorbs heat. When the temperature decreases equilibrium will shift in the exothermic direction, in the direction that releases heat.
• Pressure – If the reaction consists of only liquid and solid reactants and products, pressure has no effect in the equilibrium.

  In gas reactions if the number of moles has no change then there will be no effect by pressure on equilibrium.

  If pressure increases then equilibrium will shift to the direction having less number of molecules and if pressure decreases system will shift to the direction having more number of molecules.