Gas Variables

Q.
As the pressure of a fixed mass of a gas is increased at constant temperature, the density of the gas (increases, decreases, remains the same).
A.
The Ideal Gas Law, PV = nRT can be changed to PV = (mass/formula mass)RT. That can be rearranged to:
(P)(formula mass) = )(mass/V)RT or:
P*(formula mass) = DRT. This shows that pressure is proportional to density (they both increase at the same ratio).

Q.
As the absolute temperature of a fixed mass of an ideal gas is increased at constant pressure, the volume occupied by the gas (increases, decreases, remains the same).
A.
Again, PV = nRT. Volume is proportional to absolute temperature.

Q.
The absolute temperature of a fixed mass of ideal gas is tripled while its volume remains constant. The ratio of the final pressure of the gas to its initial pressure is (3 to 1, 1 to 1, 1.5 to 1, or 9 to 1) I think it is 3 to 1.
A.
P1V1/T1 = P2V2/T2
If V1 = V2, the above formula becomes: P1/T1 = P2/T2 or by rearranging, P2/P1 = T2/T1
That last relationship shows that at constant volume, the pressure ratio equals the temperature ratio