Question

Calculate the vapor pressure at 50 Celsius of a coolant solution that is 55.0:45.0 ethylene glycol to water by volume. At 50.0 Celsius, the density of water is .9880 g/mL, and it’s vapor pressure is 92 torr. The vapor pressure of ethylene glycol is less than 1 torr at 50.0 celsius

Answer 1

given data,

density of water= 0.9880 g/ml at 50^oC,

ethylene glycol: water ratio= 55:45

vapour pressue of water = 92 torr

Density = mass/volume

mass of water = 45 x 0.9880

=44.46 g

mass of ethylene glycol = 55 x 1.11 (density of ethylene glycol)

= 61.05 g

moles of ethylene glycol = (61.05 x1 )/ 62.07

=0.983 moles

moles of H₂O = (44.46 x 1) / 18

= 2.47moles

total moles = 0.983 +2.47

= 3.453

mole fraction of water = 2.47/3.453

= 0.7153

vapor pressure of solution = 0.7153 x 92 torr

=65.80 torr