Question

An 14.7 g of an unknown non-ionizing solute is added to 95.7 g of water. If the boiling point of the solution is 101.3, what is the molar mass of the solute?

Answer 1

Dela increased boiling temperature is determined first:
T = 101.3 to 100 = 1.3 ° C
As the solvent is water the constant value
is 0.52 ºC.m
The equation of temperature rise is boiling
T = K.m
molality equation is
m = moles of solute / Kg solvent
kg solvent = 0,0957kg
replacing all and leaving a function of the moles of solute is:
* 1.3 = 0.52 mol solute / 0.0957
moles of solute = 0.2393 mol
Molecular weight = mass / mol
Molecular weight = 14.7 / 23.93 = 61.442