Graham's Law and Dalton's law. Have a test tomorrow!!?

Question

Graham's Law
Q: How many times faster does oxygen effuse than CO2?

Dalton's law of partial pressures.
Q: Gases A,B, and C are in an enclosed container. The partial pressure of A is 2.0 atm, the partial pressure of C is 3.0 atm, and the total pressure in 10.0 atm. What is the partial pressure of B?

Please tell me answers and give me some explanations.

Answer 1

1 root 44/root 32 faster

2. 10 - (2 + 3) = 5

Answer 2

Graham's Law states that the rate of effusion of a gas is proportional to the square root of the reciprocal of the density (1/density)^(1/2)

The rate of effusion of O2 divided by the rate of effusion of CO2 = square root of the quantity (the MW of CO2 divided by the MW of O2). The square root of (44/32) = 1.1726, so O2 effusion rate is 1.1726 times as fast. Why did I use MW instead of densities? Because density is proportional to MW (1 mole of all ideal gases occupy 22.4 L at STP).

Dalton's Law of Partial Presures states that the total pressure equals the sum of the partial pressures. 10 atm - 2 atm - 3 atm = 5 atm (the partial pressure of gas B)