The given question is incomplete, the complete question is:
Determine the vapor pressure (in atm) of water in an aqueous solution of 12% by mass ethylene glycol (antifreeze) if the vapor pressure of pure water at that temperature is 0.095 atmospheres.
Answer:
The correct answer is 0.091 atm.
Explanation:
Based on the given information, the mass of ethylene glycol is 12% by mass, which means 12 grams of ethylene glycol dissolved in 88 grams of water.
The moles of a substance can be determined by using the formula,
Moles = Weight/molecular mass
Number of moles of water = mass/molecular mass
= 88g/18g/mol
= 4.88 moles
Number of moles of ethylene glycol = Mass/molecular mass
= 12 grams/62g/mol
= 0.193 moles
Mole fraction of water will be,
Mole fraction = number of moles of water/Number of moles of water+Number of moles of ethylene glycol
Mole fraction = 4.88/4.88+0.193
= 0.961
Vapor pressure of water can be determined by using the formula,
Vapor pressure = Vapor pressure of pure water * Mole fraction of water
= 0.095 * 0.961
= 0.091 atm.
