Question

The vapor pressure of benzene is 100.0 mmhg at 26.1°c. calculate the vapor pressure of a solution containing 28.2 g of camphor (c10h16o) dissolved in 94.8 g of benzene. (camphor is a low-volatility solid.

Answer 1

To calculate the vapor pressure of a benzene solution with camphor, use Raoult's Law considering the negligibility of camphor's vapor pressure and determine the mole fraction of benzene.

Step-by-step explanation:

Calculating Vapor Pressure of a Solution

To calculate the vapor pressure of a solution containing 28.2 g of camphor (C10H16O) dissolved in 94.8 g of benzene, we can use Raoult's Law. This law states that the partial vapor pressure of a solvent in a solution is equal to the vapor pressure of the pure solvent times the mole fraction of the solvent in the solution. The formula is P1 = X1 * P1o, where P1 is the vapor pressure of the solvent in the solution, X1 is the mole fraction of the solvent, and P1o is the vapor pressure of the pure solvent.

First, we need to calculate the mole fraction of benzene in the solution. To do that, we must find the moles of both camphor and benzene using their respective molar masses (152.23 g/mol for camphor and 78.11 g/mol for benzene). After calculating the moles, we can find the mole fraction of benzene (X1) by dividing the moles of benzene by the total moles of both compounds. We can then apply the equation above to find the new vapor pressure of the benzene in the solution (vapor pressure of a solution).

Note that this calculation assumes camphor has negligible vapor pressure, which is a reasonable assumption given it is a low-volatility solid. The answer will be in mmHg because that is the unit given for the vapor pressure of pure benzene.

Answer 2

Answer: Moles C10H16O = 24.6 g/ 153.23 g/mol = 0.161 Moles benzene = 98.5 g / 78.1121 g/mol = 1.26 Mole fraction benzene = 1.26 / 1.26 + 0.161 = 0.887 vapor pressure = 100 x 0.887 = 88.7 mm Hg