Chapter 13, Problem 74QRT

Interpretation Introduction

Interpretation:

The mass of glycol that must be added to each quart of water to give freezing protection down to $\text{-31}{\text{.0}}^{\text{o}}\text{C}$ has to be calculated.

Concept Introduction:

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

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

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,

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