Calculate the molar mass of an unknown solid (assume a non-electrolyte), if 1.35 grams of th esolid was dissolved in 15.0 grams of dodecanol and caused a freezing point depression of 2.34
Mass of solid dissolved m1 = 1.35 g Mass of dodecanol m2 = 15 g Freezing point depression Td= 2.34 C Freezing point depression constant for dodecanol K = 2.9 C/mol Calculating the molarity of dodecanol m => Td = K x molarity => 2.34 = 2.9 x molarity => molarity = 2.34 / 2.9 Molarity M = 0.807 We have mass and molarity, calculating for molarity for 15 g solvent = 15 x (0.806 / 1000) = 0.0121 Now calculating the molar mass of solid = m1 / molarity => 1.35 / 0.0121 = 111.538 So the molar mass of the Solid is 111.54
