Chapter 16, Problem 16.130SP

Interpretation Introduction

Interpretation:

For the given the chemical reactions, standard enthalpy $\Delta H_{rxn}^{°}$ values should be calculated and it has to be compared and commented.

Concept Introduction:

Enthalpy changes: The changes in enthalpy that accompanies the formation of one mole of the compound at its normal state from its constituent elements in their standard state.

Standard enthalpy changes$\Delta H_{rxn}^{°}$: The heat change when molar quantities of reactants as specified by the chemical equation react to form products standard conditions.

The enthalpy change is the heat evolved or absorbed when a reaction takes place at constant pressure.

For example

  $2H_2(g)+O_2(g)\underset{}{\to }2H_{2}O(l)\Delta {{\rm H}}_f^0=-572{\text{kJ/mol}}^{\text{-1}}$

Enthalpy neutralization: The enthalpy change when one mole of acid $(H^{+})$ is neutralized with one mole of base ($O{H}^{-}$) to from one mole of water.

For example: $HCl(aq)+NaOH(aq)\underset{}{\to }NaCl(aq)+H_{2}O(l)+Heat$