Chapter 15, Problem 15.4P

Interpretation Introduction

Interpretation:

Mass of $\text{Freon-12}$ and tetrafluoroethane required to vaporize to freeze a tray of 16 ounces of ice cube has to be determined.

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 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 is needed to overcome the interactions between the liquid molecules.

The formula to calculate the time required to transfer heat energy is as follows:

  $\text{time}=\frac{\text{heat}\text{energy}}{\text{heating rate}}$