The coolant in automobiles is often a 50/50 % by volume mixture of ethylene glycol, C2H6O2, and water. At 20°C, the density of ethylene glycol is 1.1088 g/mL and the density of water is 0.9982 g/mL. What is the expected freezing point of a 50/50(v/v)% ethylene glycol/water solution? Kf = 1.86°C/m for water.

Respuesta :

Explanation:

Let the volume of the solution be 100 ml.

As the volume of glycol = 50 = volume of water

Hence, the number of moles of glycol = [tex]\frac{mass}{molar mass}[/tex]

                                                  = [tex]\frac{density \times volume}{molar mass}[/tex]

                         = [tex]\frac{1.1088 \times 50}{62 g/mol}[/tex]

                         = 0.894 mol

Hence, number of moles of water = [tex]\frac{50 \times 0.998}{18}[/tex]

                                             = 2.77

As glycol is dissolved in water.

So, the molality = [tex]0.894 \times \frac{1000}{49.92}[/tex]

                           = 17.9

Therefore, the expected freezing point = [tex]-1.86 \times 17.9[/tex]

                                                                  = [tex]-33.31^{o}C[/tex]

Thus, we can conclude that the expected freezing point is [tex]-33.31^{o}C[/tex].