Ethylene glycol CH2OHCH2OH is a common automobile antifreeze

Ethylene glycol

CH₂(OH)CH₂(OH) is a common automobile antifreeze. Calculate the freezing point and boiling point of a solution containing 273 g of ethylene glycol and

1065 g of water.

(K_b and K_f for water are 0.52 C/m and 1.86 C/m, respectively.)

1- freezing point in C?

2- boiling point in C?

Solution

mass of ethylene glycol = 273 g

moles of ethylene glycol = 273 / 62.07 = 4.398 mol

mass of water = 1065 g

molality = moles / mass of solvent

             = 4.398 / 1.065

molality = 4.13 m

1)

delta Tf = Kf x m

0 - Tf = 1.86 x 4.13

Tf = - 7.68

freezing point = - 7.68 oC

2)

delta Tb = Kb x m

Tb - 100 = 0.52 x 4.13

Tb = 102.15 oC

boiling point = 102.15 oC