Chapter 14, Problem 72E

Interpretation Introduction

Interpretation:

The mass percent of sucrose present in an aqueous sucrose solution to raise the boiling point to 100.00 ⁰C at pressure 749.2 mmHg should be determined.

Concept introduction:

Boiling point elevation of a solvent occurs due to the addition of nonvolatile solute. The amount that the boiling point is elevated is proportional to the mole fraction of the solute. In dilute solutions, solute mole fraction is equal to its molality. The boiling point elevation can be determined by

$\Delta T_b=K_b\times m$

$\Delta T_b$ - boiling point elevation (⁰C)

$K_b$ - proportionality constant ( ⁰C mol-1 kg) (depends on boiling point, enthalpy of vaporization, molar mass of the solvent)

m − molality (mol/kg)