Use the combined gas law

Question

The pressure of a gas is decreased from 400 kPa to 200 kPa &the temperature is raised from 200 K to 300 K. The volume of the gas will:

a) Decrease by half
b) Remain the same
c) Increase by two times
d) Increase by three times
e) Increase by four times

Answer 1

The combined gas law can be represented as P1V1/T1 = P2V2/T2.  Substituting the given values, you have...

(400 kPa)(V1)/200K = (200 kPa)(V2)/300K

Solve for the ratio of V2/V1:

V2/V1 = (400)(300)/(200)(200) = 3 

So, volume will increase by 3 times (answer d)