Instant cold packs used to treat athletic injuries contain solid $N{H}_{4}N{O}_3$ and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dissolves, lowering the temperature because of the endothermic reaction

$N{H}_{4}N{O}_3(s)+H_{2}O(l)N{H}_{4}N{O}_3(aq)H$

$=+25\mathrm{.}7kJ.$

Review I Constants I Periodic Table

Part A

What is the final temperature in a squeezed cold pack that contains $47\mathrm{.}5g$ of $N{H}_{4}N{O}_3$ dissolved in $125mL$ of water? Assume a specific heat of $4\mathrm{.}18\frac{J}{g*C}$ for the solution, an initial temperature of $30\mathrm{.}0C,$ and no heat transfer between the cold pack and the environment.

$T_f=,C$

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