Chapter 4, Problem 76QRT

(a)

Interpretation Introduction

Interpretation:

The balanced thermochemical expression for formation of given compound ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}\left(\text{s}\right)$ has to be determined.

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.

Explanation of Solution

Given: ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}\left(\text{s}\right)$

The balanced expression for formation of one mole ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}\left(\text{s}\right)$ with ${\Delta }_f{H}^{\circ }$ value taken from appendix is as follows,

    $2Al\left(s\right)+\frac{3}{2}{O}_2\left(g\right)\to A{l}_2{O}_3\left(s\right){\Delta }_f{H}^{\circ }\text{ = -1675}\text{.7kJ}$

(b)

Interpretation Introduction

Interpretation:

The balanced thermochemical expression for formation of given compound ${\text{TiCl}}_{\text{4}}\left(\text{l}\right)$ has to be determined.

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.

Explanation of Solution

Given: ${\text{TiCl}}_{\text{4}}\left(\text{l}\right)$

The balanced expression for formation of one mole ${\text{TiCl}}_{\text{4}}\left(\text{l}\right)$ with ${\Delta }_f{H}^{\circ }$ value taken from appendix is as follows,

    $Ti\left(s\right)+2C{l}_2\left(g\right)\to {\text{TiCl}}_{\text{4}}\left(\text{l}\right){\Delta }_f{H}^{\circ }\text{ = -804}\text{.2kJ}$

(c)

Interpretation Introduction

Interpretation:

The balanced thermochemical expression for formation of given compound ${\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}\left(\text{s}\right)$ has to be determined.

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.

Explanation of Solution

Given: ${\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}\left(\text{s}\right)$

The balanced expression for formation of one mole ${\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}\left(\text{s}\right)$ with ${\Delta }_f{H}^{\circ }$ value taken from appendix is as follows,

    $N_2\left(g\right)+2H_2\left(g\right)+\frac{3}{2}{O}_2\left(g\right)\to {\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}\left(\text{s}\right){\Delta }_f{H}^{\circ }\text{ = -365}\text{.56kJ}$

(d)

Interpretation Introduction

Interpretation:

The balanced thermochemical expression for formation of given compound ${\text{CH}}_{\text{3}}\text{OH}\left(\text{l}\right)$ has to be determined.

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.

Explanation of Solution

Given: ${\text{CH}}_{\text{3}}\text{OH}\left(\text{l}\right)$

The balanced expression for formation of one mole ${\text{CH}}_{\text{3}}\text{OH}\left(\text{l}\right)$ with ${\Delta }_f{H}^{\circ }$ value taken from appendix is as follows,

    $C\left(s\right)+2H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to {\text{CH}}_{\text{3}}\text{OH}\left(\text{l}\right){\Delta }_f{H}^{\circ }\text{ = -238}\text{.66 kJ}$