Answer to Question #329869 in General Chemistry for Tesha

Question

1. What is the boiling point and freezing point of a solution containing 6 g of

glycerol (C3H8O3) in 25 g of water?

2. What is the molecular mass of a solute in a solution containing 3.8 g of

nonelectrolyte in 420 g of water which freezes at -23 oC?

Answer 1

ΔT = K_b*molality

Moles = 6 / 92 = 0.065 mol

Molality = 0.065 / 0.025 = 2.6

ΔT = 0.51 * 2.6 = 1.33

T2 = 100 + 1.33 = 101.33⁰C

 

ΔT = K_f*molality

ΔT = 1.86 * 2.6 = 4.84

T2 = 0 – 4.84 = -4.84