Chapter 14, Problem 14.132P

Interpretation Introduction

Interpretation:

The chemical equation for the breakdown of ${\text{H}}_{\text{2}}$ to $\text{H}$ atoms and for the subsequent

overall reaction of the $\text{H}$ atoms with oxygen has to be written. Also, the standard enthalpy of each reaction has to be calculated.

Concept Introduction:

Hess's Law:

• The enthalpy change along with a chemical reaction is self-determining of the route by which the chemical reactions take place.
• The enthalpy change of a reaction is equal to were the reaction take place in a single step or multiple steps.

Formula:

$\text{ΔH}\left(\text{total}\right)\text{= }{\displaystyle \sum \text{ΔH}}\left(\text{number of steps}\right)\mathrm{......}\text{(1)}$

Rules:

• The sign of enthalpy is inverted when the reaction is inverted.
• The amounts of reactants and products are straight comparative to the level of ΔH in a reaction. If the coefficients in a balanced reaction are multiplied by numeral, the ΔH value is multiplied by the similar numeral.