A rigid 2.00 L flask at 298 K contains an ideal‐gas mixture of CO₂(g), O₂(g)
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A rigid 2.00 L flask at 298 K contains an ideal‐gas mixture of CO₂(g), O₂(g), and He(g) at a total pressure of 750 torr. An aqueous NaOH solution is injected, completely absorbing all of the CO₂(g) without affecting the other gases. After absorption, the total pressure in the flask (still at 298 K) is 615 torr. Before the absorption took place, the amount of O₂(g) in the flask was exactly twice the amount of He(g).
(a) Express the initial amounts (in moles) of O₂(g) and He(g) in terms of a single symbolic variable.
(b) Use the pressure data to determine the actual number of moles of He(g) and O₂(g) present in the flask before CO₂(g) was absorbed.
(c) Calculate the initial number of moles of CO₂(g) and the initial partial pressure of each gas in the mixture.
(d) Which component had the greatest mole fraction in the original mixture? Support your answer quantitatively.