Chapter 4, Problem 4.22NP

(a)

Interpretation Introduction

Interpretation:

The value of $\Delta U$ and $\Delta H$ should be calculated for the combustion of 1 mole of sucrose.

Concept Introduction:

Number of moles is defined as the ratio of mass to the molar mass.

  $\text{Number of moles =}\frac{\text{mass}}{\text{molar mass}}$

The mathematical expression of change in internal energy is:

  $\Delta \text{U = }\Delta \text{H}-\Delta n_{g}RT$

Where,

  $\Delta \text{U}$ = Change in internal energy

  $\Delta H$ = Change in enthalpy

  $\Delta n_g$ = Change in number of moles of gaseous components

  $R$ = Universal gas constant

  $T$ = Temperature

The mathematical expression of change in enthalpy per mole of sucrose is:

  $\Delta H\text{ per mole of sucrose}=\frac{\text{Total heat of combustion}}{\text{Total number of moles}}$

(b)

Interpretation Introduction

Interpretation:

The value of $\Delta H_f^o$ should be calculated for sucrose.

Concept Introduction:

The mathematical expression for the standard enthalpy change value at room temperature is:

  $\Delta H{°}_R={\displaystyle \sum \text{n}}\text{H°(products})-{\displaystyle \sum \text{p}}\text{H°(reactants)}$

Where, n and p represents the coefficients of reactants and products in the balanced chemical equation.

(c)

Interpretation Introduction

Interpretation:

The heat capacity of calorimeter and its contents should be calculated.

Concept Introduction:

The mathematical expression for heat capacity at constant volume is:

  $C_V=\frac{q_V}{\Delta T}$

Where, $C_V$ = heat capacity at constant volume.

  $q_V$ = heat energy

  $\Delta T$ = Change in temperature