A chemist measures the compressibility factor Z of carbon dioxide at 300 K over a…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A chemist measures the compressibility factor Z of carbon dioxide at 300 K over a wide pressure range. The values obtained are summarized below.
Pressure (atm) → 0.10 5.0 20 50 100
Z → 0.996 0.90 0.80 1.05 1.30
Assume the temperature remains constant during the entire compression process.
(a) Describe the overall trend in Z as the pressure increases from 0.10 atm to 100 atm. Identify the approximate pressure interval over which attractive intermolecular forces dominate the behavior of the gas.
(b) Explain, in terms of competing molecular-level effects, why Z initially falls below 1 and later rises above 1 as the pressure continues to increase.
(c) Based on the pattern in the data, predict qualitatively how Z is expected to change if the gas is further compressed to 300 atm. Justify your prediction.