Answer to Question #297918 in General Chemistry for Phia

Question

A solution prepared by adding 10g of an unknown non-volatile, non-electrolyte solute to 150 g of water. The Boiling point of the solution is elevated by 0.433 0C above the normal boiling point of the solvent. What is the molar mass of the unknown substance?

Answer 1

∆T_f = iK_fm

For water, K_f = 1.86⁰ c/kg/mol

i= 1

m= molality of solution.

0.433=1×1.86×(10÷molar mass)×1000÷150

0.433= 124÷molar mass

molar mass=124÷0.433

=286.37