Question

What is the boiling point elevation of a solution prepared by dissolving 0.500 mol of sugar in 0.750 kg of water?0.3410.7681.24792

Answer 1

1) List known data.

Moles of sugar: 0.500

Mass of water: 0.750 kg

2) List unknown data.

Boiling point elevation:

3) Set the equation for boiling point elevation

$\Delta T=K_bm$

ΔT: change in temperature

Kb: Ebulloscopic constant (0.512 ºC/molal).

m: molality.

4) Molality of the solution

$m=\frac{\text{moles of solute}}{\text{kilograms of solvent}}$$m=\frac{0.500\text{ mol of sugar}}{0.750\text{ kg of water}}=0.6667m$

5) Plug in values in the equation

$\Delta T=\frac{0.512ºC}{\text{molal}}\cdot0.6667\text{ molal=0.3413ºC}$

The change in the boiling point is 0.341ºC.