Chapter 8, Problem 8.53SP

Interpretation Introduction

Interpretation:

The final temperature in a squeezed cold pack containing $50.0\text{ g}$ of $N{H}_{4}N{O}_3$ dissolved in $125\text{ mL}$ of water has to be calculated.

Concept Introduction:

The heat content of the system is termed as enthalpy and it is represented by ‘H’. It is the sum of internal energy ‘E’ and product of volume and pressure,

$H=E+PV$

$\Delta H$ refers to change in enthalpy.  Since enthalpy corresponds to the heat content of the system, change in enthalpy $\Delta H$ corresponds to change in heat content of the system at constant pressure and hence it is equivalent to $q_p.$  Thus,

$\Delta H=n\times q_p$

Where,

 $\begin{array}{l}{q}_p=heat\text{ absorbed or released at constant pressure}\\ \text{n}\text{= no}\text{.of moles}\end{array}$