# Worksheet: The Clausius–Clapeyron Equation

In this worksheet, we will practice using the Clausius–Clapeyron equation to convert between changes in temperature and vapor pressure.

Q1:

Under 101.3 kPa of atmospheric pressure, the boiling point of acetone is and the enthalpy of vaporization is 31.3 kJ/mol. Estimate the vapor pressure of acetone at .

Q2:

The vapor pressure of isooctane is 10.0 kPa at and 100.0 kPa at . Estimate the enthalpy of vaporization of isooctane.

Q3:

The vapor pressure of ethanol is 5.95 kPa at and 75.0 kPa at . Estimate the enthalpy of vaporization of ethanol.

Q4:

When the temperature of a liquid is increased, the vapor pressure increases from to . How does the ratio vary with the enthalpy of vaporization?

• AExponentially
• BLinearly
• CLogarithmically
• EInversely

Q5:

For a compound , what enthalpy change is associated with the shown process?

• AEnthalpy of fusion
• BEnthalpy of vaporization
• CEnthalpy of formation
• DLattice enthalpy
• EEnthalpy of sublimation

Q6:

The normal boiling point of is 331.9 K, and its vapor pressure at 298 K is 0.287 atm. Within the approximations inherent to the Clausius–Clapeyron equation, what value of , the molar enthalpy of vaporization, for would be compatible with this data?

Q7:

At , the vapor pressure of chloroform is 22.4 kPa and the enthalpy of vaporization is 31.40 kJ/mol. Estimate the boiling point of chloroform under 1 bar of atmospheric pressure.

Q8:

Under 1.00 bar of atmospheric pressure, the boiling point of furan is and the enthalpy of vaporization is 27.71 kJ/mol. Estimate to 3 significant figures the vapor pressure of furan at .

Q9:

Under 1.000 bar of atmospheric pressure, the boiling point of nitromethane is . The vapor pressure at is 15.48 kPa. Estimate to 3 significant figures the enthalpy of vaporization of nitromethane.

Q10:

Which of the following statements is incorrect?

• ATwo phases at equilibrium must have the same pressure.
• BThe maximum number of phases that can coexist in a system composed of four components is equal to six.
• CIt is impossible for four phases of a single pure substance to coexist at equilibrium.
• DThe Clausius–Clapeyron equation can be used in the characterization of solid–liquid phase equilibria.

Q11:

Which of the following provides a succinct statement of the Clausius inequality?

• A for all isothermal processes carried out reversibly or irreversibly at a constant temperature .
• B for all spontaneous processes occurring in any kind of system.
• C for a spontaneous process occurring in an isolated system.
• D for any reversible process carried out at a constant temperature .