Chapter 7, Problem 7.156CQ

(a)

Interpretation Introduction

Interpretation: If the reaction is endothermic or exothermic should be calculated.

Concept Interpretation: If the reaction is endothermic or exothermic depends on the sign of change in enthalpy of the reaction. The positive sign indicates hear is required in the reaction and the reaction is endothermic and the negative sign indicates heat is released and the reaction is exothermic.

(b)

Interpretation Introduction

Interpretation: The amount of heat released in kilojoules when 2.50 moles of ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$reacts should be calculated.

Concept Interpretation: The number of moles can be calculated using the following relation:

  $n=\frac{m}{M}$

Here, m is mass in grams and M is molar mass is g/mol.

If amount of heat required from 1 mol is given, it can be calculated for any number of moles by unitary method.

(c)

Interpretation Introduction

Interpretation: The amount of heat released in kilojoules when 2.75 g of ${\text{O}}_{\text{2}}$is produced should be calculated.

Concept Interpretation: The number of moles can be calculated using the following relation:

  $n=\frac{m}{M}$

Here, m is mass in grams and M is molar mass is g/mol.

If amount of heat required from 1 mol is given, it can be calculated for any number of moles by unitary method.