A cylinder contains oxygen gas at a temperature of 7ºC and a pressure of 15 atm in a volume of 100 L.A fitted piston is lowered into the cylinder,decreasing the volume occupied by the gas to 80 L and raising the temperature to 40ºC.The gas pressure is now approximately
A)3040 atm
B)595 atm
C)108 atm
D)21 atm
E)17 atm

Question

Quizplus · Accepted Answer

The pressure of the gas after the change can be calculated using the combined gas law, which is $P_1V_1/T_1 = P_2V_2/T_2$, where $P$ is pressure, $V$ is volume, and $T$ is temperature in Kelvin. First, convert temperatures to Kelvin: $7^\circ C = 280 K$ and $40^\circ C = 313 K$. Then, solve for $P_2$: $P_2 = P_1V_1T_2 / (V_2T_1) = 15 atm \times 100 L \times 313 K / (80 L \times 280 K) \approx 21 atm$.

A Cylinder Contains Oxygen Gas at a Temperature of 7ºC