Question

An aqueous solution containing 3.42 grams per woo grams of water had a freezing point depression of 0.186°c.calculate mass of solute

Answer 1

$\Delta T=KC_m=K·\frac{m_{salt}}{M_{salt}·m_{H_2O(kg)}}$

$M_{salt}=\frac{K·m_{salt}}{\Delta T·m_{H_2O(kg)}}=\frac{1.86·3.42}{0.186·0.001}=34200g/mol$