Hess's Law

Write out the reaction:

$N{H}_{4}Cl(s)longrightarrowN{H}_3(g)+HCl(g)$

As a series of steps using the given reactions:

Reaction

$N{H}_{4}Cl(s)longrightarrowN{H}_{4}Cl(aq)$

$HCl(aq)+N{H}_3(aq)longrightarrowN{H}_{4}Cl(aq)$

$N{H}_3(g)longrightarrowN{H}_3(aq)$

$HCl(g)longrightarrowHCl(aq)$

Heat of reaction

$H_1=14\mathrm{.}7k\frac{J}{m}ol$

$H_2=-52\mathrm{.}1k\frac{J}{m}ol$

$H_3=-34\mathrm{.}1k\frac{J}{m}ol$

$H_4=-74\mathrm{.}9k\frac{J}{m}ol$

Use Hess's law to calculate the overall reaction enthalpy $(k\frac{J}{m}ol)$ :

$-146\mathrm{.}4$

$($A$)$