Chapter 7, Problem 111IAE

Interpretation Introduction

(a)

Interpretation:

In the given data, the reason for the difference in the values of standard enthalpy of formations needs to be explained.

Concept introduction:

The enthalpy of reaction can be calculated using the following relation.

$\Delta H_{rxn}={\displaystyle \sum n_p\Delta H_f\left(\text{products}\right)-{\displaystyle \sum n_r\Delta H_f\left(\text{reactants}\right)}}$

Here, $\Delta H_f\left(\text{products}\right)$ is change in enthalpy of formation of product, $n_p$ is number of moles of product, $\Delta H_f\left(\text{reactants}\right)$ is change in enthalpy of formation of reactant and $n_r$ is number of moles of reactant.

Interpretation Introduction

(b)

Interpretation:

In the infinite dilute solution, the value of standard enthalpy of formation for sulfuric acid is $-909.3kJ/mol$. This value needs to be confirmed.

Concept introduction:

The enthalpy of reaction can be calculated using the following relation.

$\Delta H_{rxn}={\displaystyle \sum n_p\Delta H_f\left(\text{products}\right)-{\displaystyle \sum n_r\Delta H_f\left(\text{reactants}\right)}}$

Here, $\Delta H_f\left(\text{products}\right)$ is change in enthalpy of formation of product, $n_p$ is number of moles of product, $\Delta H_f\left(\text{reactants}\right)$ is change in enthalpy of formation of reactant and $n_r$ is number of moles of reactant.

Interpretation Introduction

(c)

Interpretation:

The temperature change for the process needs to be determined, if 500.0 mL of 1.00 M $\left[{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(aq\right)\right]$ solution is prepared from pure ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(l\right)$.

Concept introduction:

The molarity of solution is related to number of moles of solute and volume of solution in L as follows:

$M=\frac{n}{V}$

The number of moles of any substance is related to mass and molar mass as follows:

$n=\frac{m}{M}$

The heat released or absorbed in a reaction can be calculated as follows:

$q=mC\Delta T$

Here, m is mass, C is specific heat capacity and $\Delta T$ is change in temperature.