Two gases start to escape from a container and one of the gases effuses 1.25 times as fast as the other one.The two gases could have been ________. A)NO and SF₆ B)CO and CO₂ C)CO₂ and Cl₂ D)Cl₂ and CO E)CO₂ and SF₆

Question

Quizplus · Accepted Answer

According to Graham's law of effusion, the rate of effusion of a gas is inversely proportional to the square root of its molar mass. Let the molar masses of the two gases be M1 and M2. If gas 1 effuses 1.25 times as fast as gas 2, we can set up the following equation:
rate of effusion of gas 1/rate of effusion of gas 2 = √(M2/M1) = 1.25
Solving for M2/M1 gives:
M2/M1 = (1.25)^2 = 1.5625
We can then look at the molar masses of the gases given in the answer choices and see that only option B fits the criteria, as the molar mass of CO (28 g/mol) is 1.5625 times greater than the molar mass of COS (22.7 g/mol). Therefore, the two gases could have been CO and COS.

Two Gases Start to Escape from a Container and One