Question

If 0.600 mol of a nonvolatile nonelectrolyte are dissolved in 3.60 mol of water, what is the vapor pressure PH2O of the resulting solution? The vapor pressure of pure water is 23.8 torr at 25 ∘C . Express your answer with the appropriate units. View Available Hint(s) Hint 1. Determine the mole fraction of wateropened hint What is the mole fraction of water, XH2O, in this solution?

Answer 1

Answer: The vapor pressure of water in the resulting solution is 20.4 torr

Explanation:

Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:

$\chi_A=\frac{n_A}{n_A+n_B}$ .....(1)

where n is the number of moles

We are given:

Moles of a non-volatile non-electrolyte = 0.600 moles

Moles of water = 3.60 moles

Putting values in equation 1, we get:

$\chi_{H_2O}=\frac{3.60}{3.60+0.600}\\\\\chi_{H_2O}=0.857$

Equation used to calculate the vapor pressure of substance A in a solution is given by:

$\text{Vapor pressure in solution}=\text{Pure vapor pressure}\times \text{Mole fraction}$

We are given:

Vapor pressure of pure water = 23.8 torr

$\text{Vapor pressure in solution}=23.8 torr\times 0.857\\\\\text{Vapor pressure in solution}=20.4torr$

Hence, the vapor pressure of water in the resulting solution is 20.4 torr