A 4.1 L sealed bottle containing 0.25 g of liquid ethanol, C2H6O, is placed in a refrigerator and reaches equilibrium with its vapor at -11°C. The vapor pressure of ethanol is 10 torr at -2.3°C and 40 torr at 19°C.

Question

A 4.1 L sealed bottle containing 0.25 g of liquid ethanol, C2H6O, is placed in a refrigerator and reaches equilibrium with its vapor at -11°C. The vapor pressure of ethanol is 10 torr at -2.3°C and 40 torr at 19°C.
(a) What mass of ethanol is present in the vapor?

DrBob222 · Answer

Step 1. Use the Clausius-Clapeyron equation to solve for delta Hvap/mol.

Step 2. Knowing delta Hvap/mol for ethanol, calculate vapor pressure of ethanol @ -11 C.

Step 3. Use PV = nRT to solve for n =number of moles of ethanol vapor at -11 C.

Step 4. moles = grams/molar mass
Solve for grams.

Check my thinking. Post your work if you get stuck.

123 · Answer

how to use the Clausius-Clapeyron equation in this question?