Chapter 13, Problem 114QRT

(a)

Interpretation Introduction

Interpretation:

Using calculations, the vodka is frozen or not has to be determined.

Concept introduction

Freezing point is the temperature at which liquid turns into solid.

The Freezing point depression ${\text{(ΔT}}_{\text{f}}\text{)}$ is indicated as ${\text{ΔT}}_{\text{f}}{\text{= K}}_{\text{f}}\text{m}$.

Where,

${\text{ΔT}}_{\text{f}}-$ Change in freezing point

${\text{K}}_{\text{f}}-$ Molal freezing point constant

$m-$ Molality of the solution

Moles: One mole is equivalent to the mass of the substance consists same number of units equal to the atoms present in $\text{12}\text{g}$ of ${}^{\text{12}}\text{C}$.

From given mass of substance moles could be calculated by using the following formula,

  $\text{Moles}\text{of}\text{substance }\text{= }\frac{\text{Given}\text{mass}\text{of}\text{substance}}{\text{Molecular}\text{mass}}$

Mass: It is the quantitative measure of a substance. The amount of matter present in substance is expressed as mass. The $S.I.$ unit of mass is $kg$.

(b)

Interpretation Introduction

Interpretation:

The boiling point of vodka has to be calculated.

Concept introduction

Boiling point is the temperature at which liquid turns into a gas. Example: boiling point of water is $\text{100°C}$. That is water changes from liquid phase to gas phase at temperature ${\text{100}}^{\text{o}}\text{C}$.

  ${\text{ΔT}}_{\text{b}}{\text{= T}}_{\text{b}}{\text{- T}}_{\text{b}}^{\text{°}}$.

Where,

  ${\text{ΔT}}_{\text{b}}-$ Change in boiling point.

  ${\text{T}}_{\text{b}}-$ Boiling point of the solution.

  ${\text{T}}_{\text{b}}^{\text{°}}-$ Boiling point of pure solvent.

The Boiling point elevation${\text{(ΔT}}_{\text{b}}\text{)}$ is indicated as ${\text{ΔT}}_{\text{b}}{\text{= K}}_{\text{b}}\text{m}$

Where,

  ${\text{ΔT}}_{\text{b}}-$ Change in boiling point.

  ${\text{K}}_{\text{b}}-$ Molal boiling point constant.

  $m-$ Molality of the solution.