A scientist investigates how simultaneous changes in temperature and external…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A scientist investigates how simultaneous changes in temperature and external pressure affect the microscopic properties of a gas and a liquid.
Two sealed containers, each of fixed volume 1.00 L, are prepared:
• Container 1 holds 0.0500 mol of nitrogen gas at 300 K.
• Container 2 holds 0.0500 mol of liquid ethanol at 300 K (no significant vapor pressure inside).
Both containers are subjected to identical conditions in a high-pressure chamber: the external temperature is raised to 500 K while an external pressure of 100 atm is applied uniformly to both containers. Assume the containers themselves do not change volume and that nitrogen remains in the gas phase.
(a) Explain qualitatively how the average spacing between nitrogen molecules changes under the new conditions. Support your answer by referring to relevant macroscopic variables.
(b) Describe how the same temperature-pressure treatment affects the average spacing between ethanol molecules in Container 2, and account for any differences relative to Container 1.
(c) Compare the expected changes in collision frequency for nitrogen molecules and ethanol molecules. Include in your discussion the role of intermolecular forces in each substance.
(d) Based on your analysis in parts (a)–(c), predict which container experiences the greater change in internal pressure. Justify your prediction.