Chapter 4, Problem 4.3NP

(a)

Interpretation Introduction

Interpretation:

The standard energy of formation ${\text{ΔU}}_{\text{f}}^{\text{0}}$ for K₂O needs to be calculated based on the given conditions which involves the combustion of a known mass of K in a constant volume calorimeter

Concept Introduction:

• Combustion is a thermochemical reaction in which a substance burns in the presence of excess oxygen to produce carbon dioxide and water.
• Combustion reactions are exothermic in nature i.e. it is accompanied by the release of energy.

(b)

Interpretation Introduction

Interpretation:

The standard enthalpy of formation ${\text{ΔH}}_{\text{f}}^{\text{0}}$ for K₂O needs to be calculated based on the given conditions which involves the combustion of a known mass of K in a constant volume calorimeter

Concept Introduction:

For a given chemical reaction, the enthalpy change ΔH can be related to the change in internal energy ΔU as:

  $\begin{array}{l}\text{ΔH = ΔU}+\text{ΔnRT ---(2)}\\ \text{where }\Delta \text{n = change in the number of moles}\\ \text{ = }{\displaystyle \sum \text{n(products)-}{\displaystyle \sum \text{n(reactants)}}}\end{array}$

  $$