According to Boyle's Law, a gas is at 1.00 atm and 5.00 L. If it is compressed isothermally to 2.50 L, what is the final pressure?

According to Boyle's Law, a gas is at 1.00 atm and 5.00 L. If it is compressed isothermally to 2.50 L, what is the final pressure?

• A. 1.50 atm
• B. 0.50 atm
• C. 3.00 atm
• D. 2.00 atm

Answer: (D)

In isothermal conditions, the product of pressure and volume stays constant for a given amount of gas, so P1V1 = P2V2. Here, P1 = 1.00 atm and V1 = 5.00 L, so P1V1 = 5.00 atm·L. The volume is compressed to V2 = 2.50 L, so P2 = (P1V1)/V2 = 5.00 / 2.50 = 2.00 atm. Since the volume halves, the pressure must double, giving a final pressure of 2.00 atm.

In isothermal conditions, the product of pressure and volume stays constant for a given amount of gas, so P1V1 = P2V2. Here, P1 = 1.00 atm and V1 = 5.00 L, so P1V1 = 5.00 atm·L. The volume is compressed to V2 = 2.50 L, so P2 = (P1V1)/V2 = 5.00 / 2.50 = 2.00 atm. Since the volume halves, the pressure must double, giving a final pressure of 2.00 atm.