Chapter 18, Problem 18.109SP

(a)

Interpretation Introduction

Interpretation:

Molar heat of vaporization of diethyl ether has to be estimated at $34.6°C$.

Concept Introduction:

Spontaneous process: A process which is initiated by itself, without the help of external energy source is called spontaneous process.  All spontaneous process is associated with the decrease in free energy in the system.

Vapour pressure: Vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in closed system.

Vapour pressure is nothing but the tendency of particles to escape from the liquid (or) solid.

Enthalpy changes: The changes in enthalpy that accompanies the formation of one mole of the compound at its normal state from its constituent elements in their standard state.

According to Trouton's rule for, various liquids at their boiling point the change in entropy value will be the same.  The ratio of enthalpy of vaporization and boiling temperature of various liquids has the same value.

  ${\text{ΔS}}_{\text{vap}}\text{=}\frac{{\text{ΔΗ}}_{\text{vap}}}{{\text{T}}_{\text{bp}}}\approx {\text{90JK}}^{\text{-1}}{\text{mol}}^{\text{-1}}$

Where,

  ${\text{ΔS}}_{\text{vap}}$ is the entropy of vaporization

  ${\text{ΔΗ}}_{\text{vap}}$ is the enthalpy of vaporization

  ${\text{T}}_{\text{bp}}$ boiling temperature

(b)

Interpretation Introduction

Interpretation:

Vapour pressure of diethyl ether has to be estimated at $20°C$.

Concept Introduction:

Spontaneous process: A process which is initiated by itself, without the help of external energy source is called spontaneous process.  All spontaneous process is associated with the decrease in free energy in the system.

Vapour pressure: Vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in closed system.

Vapour pressure is nothing but the tendency of particles to escape from the liquid (or) solid.

Enthalpy changes: The changes in enthalpy that accompanies the formation of one mole of the compound at its normal state from its constituent elements in their standard state.

According to Trouton's rule for, various liquids at their boiling point the change in entropy value will be the same.  The ratio of enthalpy of vaporization and boiling temperature of various liquids has the same value.

  ${\text{ΔS}}_{\text{vap}}\text{=}\frac{{\text{ΔΗ}}_{\text{vap}}}{{\text{T}}_{\text{bp}}}\approx {\text{90JK}}^{\text{-1}}{\text{mol}}^{\text{-1}}$

Where,

  ${\text{ΔS}}_{\text{vap}}$ is the entropy of vaporization

  ${\text{ΔΗ}}_{\text{vap}}$ is the enthalpy of vaporization

  ${\text{T}}_{\text{bp}}$ boiling temperature