Need Help In Chemistry about combined Gas Law?

Question

A sample of oxygen at 40degreesC occupies 820. mL. If this sample later occupies 1250 mL at 60degreesC and 1.40 atm, what was its original pressure?

Answer 1

The equation you need to use is:

P1V1/T1 = P2V2/T2

Also remember that your temperatures MUST be in K and your volumes SHOULD be in L.

So, for this problem, P1 is your unknown, T1 = 313 K, V1=0.820 L. P2= 1.4 atm, T2 = 333 K and V2 = 1.25 L.

Plug those into the equation and solve for P1.