Question

The vapor pressure of pure benzene is 639.7 mm, and the vapor pressure of a solution of a non-volatile solute in benzene is 637.9 mm. Calculate the mole fractions and molarity of the solution.

a.True
b.False

Answer 1

The mole fraction of benzene in the solution, calculated using Raoult's law, is approximately 0.9972. To calculate the molarity of the solution, specific mass of benzene and the volume of the solution would be needed, which is not provided in the question.

Step-by-step explanation:

The question relates to the calculation of the mole fraction and molarity of a benzene solution with a non-volatile solute and the vapor pressure of this solution. To determine the mole fraction of benzene in the solution, we will use Raoult's law, which states the partial vapor pressure of a component in a mixture is equal to the vapor pressure of the pure component multiplied by its mole fraction in the mixture.

Calculating Mole Fraction of Benzene

Let P1 be the vapor pressure of pure benzene, and Psolution be the vapor pressure of the benzene solution. The mole fraction of benzene (Xbenzene) can be calculated using the equation:

Xbenzene = Psolution / P1

Substituting the given values: Xbenzene = 637.9 mmHg / 639.7 mmHg = 0.9972 (approximate value).

Calculating Molarity of the Solution

To calculate the molarity of the solution, we need the mass of benzene, the molar mass of benzene, and the volume of the solution. However, since the exact mass and volume are not provided, we cannot provide the molarity of the solution without these specifics. Molarity is calculated as moles of solute per liter of solution.