Raolut’s Law and Clausius Clapeyron Equation Practice Problems
What is the definition of vapor pressure?
What is the formula for Raolut’s Law?
What is mole faction?
Use the table below to solve the following:
Molecule
Benzene
Ethylene glycol
Toluene
Water
Hexane
Vapor Pressure (torr) at 25 °C
95.1
.06
28.4
23.8
151.25
1. If a mixture contains 2 moles of H2O gas and 3 moles of benzene gas, what is the total vapor
pressure at 25°C?
2. If a mixture contains 15 g of hexane (C6 H14) is mixed with 12 g of ethylene glycol (C2H6O2)
what is the total vapor pressure at 25°C?
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3. If 25 g of ethylene glycol (C2H6O2) are dissolved in 100 mL of water, what is the total vapor
pressure at 25°C?
4. How much benzene (C6 H6) is present in a benzene/toluene mixture whose total vapor
pressure is 50 torr at 25°C? There is 2 g of toluene (C7H8)
5. What is the Clausius Clapeyron equation? What does each symbol stand for?
a. Rearranged for P2
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b.
Rearranged for T2
6. The vapor pressure of 1-propanol is 10.0 torr at 14.7 °C. Calculate the vapor pressure at 52.8
°C. Heat of vaporization of 1-propanol = 47.2 kJ/mol
7. Determine ΔHvap for a compound that has a measured vapor pressure of 28.3 torr at 25 °C
and 148 torr at 50 °C.
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8. A substance has a vapor pressure of 0.2020 atm at 261.5 K. If its heat of vaporization is 20.94
kJ/mol, what temperature will it have a vapor pressure of .3500 atm?
9. What is the vapor pressure of 5 g of toluene with 5 g of water at 50°C? The heat of
vaporization for water is 40.7 kJ/ mol and toluene is 38.06 kJ/mol.
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