Chapter 7, Problem 7.80GP

(a)

Interpretation Introduction

Interpretation:

$\text{ΔH}$ for the production of ammonia has to be estimated. The reaction is whether exothermic or endothermic has to be determined.

Concept Introduction:

Enthalpy $\text{H}$: it is the total amount of heat in a particular system.

The value of heat formed in a reaction $\text{ΔH}$ is calculated by the formula,

$\text{ΔH=}{{\displaystyle \sum \left(BondDissociationEnergy\right)}}_{\left(\text{reactants}\right)}-{{\displaystyle \sum \left(BondDissociationEnergy\right)}}_{\left(\text{products}\right)}$

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.

Bond dissociation energy: The energy required for the breaking of a bond between two atoms and separating it into different gas molecules

(b)

Interpretation Introduction

Interpretation:

The three ways to increase the production of ammonia has to be determined.

Concept Introduction:

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.

(c)

Interpretation Introduction

Interpretation:

The three methods used in Haber-Bosch process to increase the production of ammonia have to be determined.

Concept Introduction:

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.