Question

A sample of helium gas has a volume of 900. milliliters and a pressure of 2.50 atm at 298 K. What is the new pressure when the temperature is changed to 336 K and the volume is decreased to 450. milliliters?
(1) 0.177 atm (3) 5.64 atm
(2) 4.43 atm (4) 14.1 atm

Answer 1

The combined Boyle's and Charles' gas law says P1V1/T1 = P2V2/T2 

In this case we have (2.5 atm) (900 ml) / 298 K = (P2) (450 ml) / 336 K -----> 
7.55 = 1.34P2 -----> P2 = 7.55 / 1.34 = 5.63 atm