A sealed, rigid container initially holds three gases in the following masses: of (…
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
A sealed, rigid container initially holds three gases in the following masses: 30.0g of CO2 (44.01gmol−1), 10.0g of N2 (28.02gmol−1), and 5.00g of He (4.00gmol−1). After the mixture reaches thermal equilibrium, a valve is opened momentarily so that exactly 40.0% of the total amount of substance in the container escapes. Assume that the escaping portion has the same composition (by mole fraction) as the gas remaining in the container.
(1) Part 1: (a) Calculate the initial amount of substance (in moles) of each gas and the initial total amount in the container.
(2) Part 2: (b) Determine the number of moles of each gas that leave the container during the release.
(3) Part 3: (c) Compute the number of molecules of each gas that remain in the container after the release. Express each answer in scientific notation with units.
(4) Part 4: (d) Discuss the significance of the assumption that the escaping gas has the same composition as the original mixture. Explain how violating this assumption would affect the quantitative results obtained in parts (b) and (c).