# Glycerin, #C_3H_8O_3#, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 164 g glycerin to 338 mL #H_2O# at 39.8°C?

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The vapor pressure of pure water at 39.8°C is 54.74 torr and its density is .992 #g# #/# #cm^3# .

The vapor pressure of pure water at 39.8°C is 54.74 torr and its density is .992

##### 1 Answer

The vapour pressure of the solution is proportional to the mole fraction of the volatile component...

Here...

#### Explanation:

And so the vapour pressure will be somewhat reduced with respect to PURE water...we calculate the mole fractions of each component...

I did this the long way, but of course we know that the SUM of the mole fractions in a BINARY solution is UNITY...i.e.

And so

As is typical for aqueous solutions...