The vapor pressures of liquid ethanol and liquid 1-propanol were measured at several temperatures. Selected data are provided.
Temperature (K)
Vapor pressure of ethanol (kPa)
Vapor pressure of 1-propanol (kPa)
298
7.9
2.2
308
13.0
4.1
318
20.9
7.4
328
32.2
12.6
Answer the following questions about the two substances.
a. Part 1: (a) Without performing a calculation, identify which of the two liquids has stronger overall intermolecular forces. Cite specific evidence from the data.
b. Part 2: (b) Using the data, determine the enthalpy of vaporization, ΔHvap, for ethanol. Clearly outline the graphical or algebraic method you use and include units in your final answer.
c. Part 3: (c) Repeat the determination in part (b) for 1-propanol.
d. Part 4: (d) Compare the magnitudes of the enthalpies you obtained. Explain how these values are consistent with the predominant intermolecular forces present in each liquid.
e. Part 5: (e) At 298 K, which liquid is expected to exhibit the larger surface tension? Justify your answer using the enthalpy data and intermolecular considerations.