CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
At 300 K three different gases—methane (CH₄), ethane (C₂H₆), and hydrogen (H₂)—are studied. A researcher records the following compressibility factors.
Pressure (atm) 10 200
Z (CH₄) 0.92 1.20
Z (C₂H₆) 0.85 1.10
Z (H₂) 0.98 1.45
(a) Rank the three gases in order of increasing strength of intermolecular attractions at 10 atm. Provide a brief justification based on the data.
(b) Rank the gases in order of increasing relative importance of molecular volume effects at 200 atm. Support your ranking with evidence drawn from the values of Z.
(c) When all three gases are slowly compressed isothermally at 300 K, which gas is most likely to liquefy first? Explain your reasoning with reference to the information given.