Chapter 15, Problem 15.9P

Interpretation Introduction

Interpretation:

The heating curve for $7.50\text{g}$ of mercury from $200\text{K}$ to $800\text{K}$ with heating input of $100\text{J}\cdot {\min }^{-1}$ has to be sketched.

Concept Introduction:

Heating curve is the plot of temperature how it varies with time for a substance when it is heated at constant rate. And in the heating curve the horizontal portion is molar enthalpy. 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 absorbed by n mole of substance to undergo change is as follows:

  $q=n\left(\Delta H\right)$

Here,

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

$n$ is the number of moles of substance.

$\Delta H$ is the enthalpy for process in $\text{kJ/mol}$ .

The value of $\Delta H$ is positive always as energy needed to overcome the interactions between the liquid molecules.