Chapter 7, Problem 7.69CP

(a)

Interpretation Introduction

Interpretation:

The balanced equation for the reduction of magnetite by hydrogen is to be determined.

Concept Introduction:

Enthalpy $\left(H\right)$: 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.

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 energy needed to produce $55gFe$ in $kcal$ and $kJ$ is to be determined.

Concept Introduction:

Enthalpy $\left(H\right)$: 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.

Combustion is the process of burning of a compound; in which the compound reacts with excess of oxygen.

(c)

Interpretation Introduction

Interpretation:

The amount of $H_2$ needed to produce $75gFe$ is to be determined.

Concept Introduction:

Enthalpy $\left(H\right)$: 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.

Combustion is the process of burning of a compound; in which the compound reacts with excess of oxygen.

(d)

Interpretation Introduction

Interpretation:

At equilibrium the reaction is whether reaction or product favored is to be determined.

Concept Introduction:

Equilibrium constant: It is the ratio of products to reactants has a constant value when the reaction is in equilibrium at a certain temperature. And it is represented by the letter K.

For a reaction,

$\text{aA}\text{+}\text{bB}\rightleftarrows \text{cC}\text{+}\text{dD}$

The equilibrium constant is, $K=\frac{{\text{[C]}}^{\text{c}}{\text{[D]}}^{\text{d}}}{{\text{[A]}}^{\text{a}}{\text{[B]}}^{\text{b}}}$

where,

a, b, c and d are the stoichiometric coefficients of reactant and product in the reactions.

If $K<1$, then it is reactant favoured reaction whereas if $K>1$, then it is product favoured reaction.