Chemistry Question

Question

A sample of an ideal gas has a volume of  at  and  What is the volume of the gas at  and 

Answer 1

For an ideal gas, the important equation is the ideal gas law: PV=nRT. From the given info, we know everything except for n:

P = 1.50 atm

V = 3.15 L

n = ?

R = 0.08206 Latm/Kmol

T = 287.35 K

So we can solve for n: n = PV/RT = (1.5)(3.15)/((0.08206)(287.35)) = 0.200 moles

Now, we can solve for the 2nd set of conditions:

P = 0.992 atm

V = ?

n = 0.200

R = 0.08206 Latm/Kmol

T = 295.35 K

V = nRT/P = (0.200)(0.08206)(295.35)/(0.992) = 4.89 L

Notice in this problem, P and T are changing, which in turn affects V. n is not changing (there is no indication of gas being added or released). So we can use the first conditions to find n, and then use n in the new set of conditions.

Hope that helps!