A Suppose you have 2 L of an ideal gas at 2 atm pressure in a container equipped with a piston. You arrange to keep the temperature of the gas constant at 25 C. How much work does it take to compress the gas to a volume of 6.9 L? The units are in L-atm.

My answer was - 9.8 L*atm but it was wrong.

B) Suppose you have 4.5 L of an ideal gas at 25 C initially in a container equipped with a piston. You arrange to keep the pressure on the gas equal to 2 atm as you compress the gas to a volume of 2.1 L. How much work does it take to compress the gas?

My answer was 4.8 L*atm which was correct.