In: Chemistry
Calculate the vapor pressure at 25 ∘C of a solution containing 55.4 g ethylene glycol (HOCH2CH2OH) and 282.6 g water. The vapor pressure of pure water at 25 ∘C is 23.8 torr.
P=Po* Mole fraction of water
P = ?
Po = 23.8 torr
Molar mass of ethylene glycol = 62 g/mol
number of moles of ethylene glycol = mass / molar mass
=55.4/62
= 0.8935 mol
Molar mass of water = 18 g/mol
number of moles of water = mass / molar mass
=282.6/18
= 15.7 mol
Mole fraction of water = moles of water / total
moles
= 15.7 / (15.7 + 0.8935)
= 0.946
P = Po* Mole fraction of water
P = 23.8 * 0.946
P = 22.5 torr
Answer: 22.5 torr