There is a convenient trick to avoid having to calculate things with complex calculator entry. The general idea is that if n/N of the gas sample remain constant, you rearrange the terms so changing variables are all on the left side of the equation, while unchanging variables and constants are on the right side of the equation. Since the right side stays constant, the left side also stays constant. Now write down the left side twice, once with subscripts 1 (initial values), and again with subscripts 2 (final values), and set them equal to each other. Put in any known values, and solve to find the unknowns. This way, you never need to enter the unchanging variables or the constants in your calculator! Use this method to solve the following problem. An ideal piston contains 3 liters of gas, has a pressure of 110,000 Pa and a temperature of 20 C. The piston has a lock set that will not allow it to expand beyond 3.5 liters. You heat the piston with a Bunsen burner until the gas in the piston reaches a temperature of 400 K. This causes the piston to expand to its maximum volume.

a. Find the pressure in the piston.
b. Now you keep the gas at 400 K, but release the maximum volume lock on the piston, allowing it to expand until the pressure in the piston is once again 110,000 Pa. Find the final volume.