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
- DQuadratically
- EInversely
Q5:
For a compound , what enthalpy change is associated with the shown process?
- AEnthalpy of fusion
- BEnthalpy of vaporization
- CLattice enthalpy
- DEnthalpy of sublimation
- EEnthalpy of formation
Q6:
The normal boiling point of is 331.9 K, and its vapor pressure at 298 K is 0.287 bar. Within the approximations inherent to the Clausius-Clapeyron equation, what value of (the molar enthalpy of vaporization) for would be compatible with this data?
- A kJ/mol
- B kJ/mol
- C 33.2 kJ/mol
- D 70.6 kJ/mol
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?
- AThe Clausius–Clapeyron equation can be used in the characterization of solid–liquid phase equilibria.
- BIt is impossible for four phases of a single pure substance to coexist at equilibrium.
- CTwo phases at equilibrium must have the same pressure.
- DThe maximum number of phases that can coexist in a system composed of four components is equal to six.
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 .