CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Three gases—Ar(g), SO₂(g), and NH₃(g)—are each placed in separate, identical 2.00 L rigid flasks at 270 K. Each flask contains exactly 0.80 mol of its respective gas. The equipment available allows precise measurement of pressure at 270 K and at several higher and lower temperatures.
(a) Rank the three gases from largest to smallest expected negative deviation (difference in the direction of a lower measured pressure relative to the ideal prediction) at 270 K. Justify your ranking in terms of the dominant intermolecular attractions present in each gas.
(b) Design an experimental procedure—using only temperature control and pressure measurement—that would allow a student to confirm the ranking proposed in part (a). Outline the key steps and specify the data that must be collected.
(c) Describe how the collected data would be analyzed to quantify the magnitude of the pressure deviation for each gas at 270 K.
(d) Explain how the results of your analysis would either support or refute the initial ranking of the gases.