We are asked to calculate ΔH (in kJ/mol NH_{4}NO_{3}) for the solution process:

NH_{4}NO_{3}(s) → NH_{4}^{+}(aq) + NO_{3}^{-}(aq)

Calculate heat released by water.

$\overline{){\mathbf{q}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}{\mathbf{mC}}{\mathbf{\u2206}}{\mathbf{T}}}\phantom{\rule{0ex}{0ex}}\mathbf{q}\mathbf{}\mathbf{=}\mathbf{}\mathbf{(}\mathbf{60}\mathbf{.}\mathbf{0}\mathbf{}\mathbf{g}\mathbf{)}\mathbf{(}\mathbf{4}\mathbf{.}\mathbf{184}\mathbf{}\mathbf{J}\mathbf{/}\mathbf{g}\mathbf{-}\mathbf{\xb0}\mathbf{C}\mathbf{)}\mathbf{(}\mathbf{}\mathbf{16}\mathbf{.}\mathbf{9}\mathbf{}\mathbf{\xb0}\mathbf{C}\mathbf{-}\mathbf{22}\mathbf{.}\mathbf{0}\mathbf{}\mathbf{\xb0}\mathbf{C}\mathbf{}\mathbf{)}\phantom{\rule{0ex}{0ex}}\mathbf{q}\mathbf{}\mathbf{=}\mathbf{}\mathbf{(}\mathbf{60}\mathbf{.}\mathbf{0}\mathbf{}\overline{)\mathbf{g}}\mathbf{)}\mathbf{(}\mathbf{4}\mathbf{.}\mathbf{184}\mathbf{}\mathbf{J}\mathbf{/}\overline{)\mathbf{g}}\mathbf{-}\overline{)\mathbf{\xb0}\mathbf{C}}\mathbf{)}\mathbf{(}\mathbf{-}\mathbf{5}\mathbf{.}\mathbf{1}\overline{)\mathbf{}\mathbf{\xb0}\mathbf{C}}\mathbf{)}$

**q = -1280.3 J**

When a 4.25-g sample of solid ammonium nitrate dissolves in 60.0 g of water in a coffee-cup calorimeter, the temperature drops from 22.0 ^{o}C to 16.9 ^{o}C.

You may want to reference (Pages 179 - 183) Section 5.5 while completing this problem.

Calculate ΔH (in kJ/mol NH_{4}NO_{3}) for the solution process:

NH_{4}NO_{3}(s) → NH_{4}^{+}(aq) + NO_{3}^{-}(aq)

Assume that the specific heat of the solution is the same as that of pure water.

**Is this process endothermic or exothermic?**

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