Chapter EN, Problem 7PQ

Interpretation Introduction

Interpretation:

Reason for more heat released when $1\text{g}$ of steam is converted from $100°\text{C}$ to $50°\text{C}$ than $1\text{g}$ liquid that is also converted from $100°\text{C}$ to $50°\text{C}$ has to be explained.

Concept Introduction:

Molar enthalpy for a process is the quantity of heat energy needed by one mole of a substance to undergo change in the process. The heat energy needed to change the temperature of $n$ moles of substance from $T_1$ to $T_2$ is as follows:

  $q=nC\left(T_1-T_2\right)$

Here,

  $q$ is the heat energy in $\text{kJ}$.

  $n$ is of moles of substance.

  $C$ is specific heat capacity of substance.

  $T_1$ and $T_2$ are initial and final temperature of substance respectively.