Question

Glycerin, C3H8O3, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 164 g glycerin to 3.38 mL H2O at 39.8°C? The vapor pressure of pure water at 38.8°C is 54.74 torr, and its density is 0.992 g/cm^3. Does this have to do with Henry's Law? Can someone help explain this to me? Thanks.

a) True
b) False

Answer 1

Yes, this question involves Henry's Law. The vapor pressure of the solution will mainly be determined by the vapor pressure of water. To calculate the vapor pressure, use the equation: Vapor pressure of solution = Vapor pressure of pure water * Mole fraction of water in solution.

Step-by-step explanation:

Yes, this question does involve Henry's Law. Henry's Law states that the vapor pressure of a gas over a liquid is directly proportional to the concentration of the gas in the liquid. In this case, you are adding glycerin, a nonvolatile liquid, to water. Glycerin does not evaporate easily and therefore does not contribute significantly to the vapor pressure of the solution. So, the vapor pressure of the solution will be mainly determined by the vapor pressure of water. To calculate the vapor pressure, you can use the equation:

Vapor pressure of solution = Vapor pressure of pure water * Mole fraction of water in solution

Assuming the solution is ideal, the mole fraction of water can be calculated using the density of water and the masses of water and glycerin. Once you have the mole fraction of water, you can substitute it into the equation to find the vapor pressure of the solution.