The Richard Stockton College of New Jersey
Chemistry Program, School of Natural Sciences and Mathematics
PO Box 195, Pomoma, NJ
CHEM 3410: Physical Chemistry I — Fall 2008
In-class Practice Problems
September 10, 2008
1. Suppose we have 1 mole of an ideal gas confined in a cylinder with a movable piston top, which
allows the volume of the gas to be controlled. The gas starts at an initial volume Vo= 10 L at a
pressure of 1 atm.
We want to consider the amount of work done during three different processes, each of which starts
with the gas in the same initial state and ends with the gas in the same final state:
(a) (i) The gas is compressed to a volume of 1 L at constant pressure (P = 1 atm). (ii) The
pressure is then slowly increased from 1 atm to 10 atm at constant volume.
(b) (i) The pressure is slowly increased from 1 atm to 10 atm at constant volume (V = Vo). (ii)
The gas is then compressed from 10 L to 1 L at constant pressure (P = 10 atm).
(c) The gas is isothermally compressed from a volume of 10 L to 1 L.
Assume the changes occur slowly enough for the gas to remain in equilibrium at all times (reversible
processes).
2. One mole of a monatomic ideal gas, initially at 20.0◦C and 1.00 ×106Pa undegoes a two-stage
transformation. For each stage calculate the final pressure, as well as, q,w, ∆U, and ∆H. Calculate
q,w, ∆U, and ∆Hfor the complete process.
(a) The gas is expanded isothermally and reversibly until the volume doubles.
(b) Beginning at the end of the first stage, the temperature is raised to 80.0◦C at constant volume.
3. A diatomic ideal gas is allowed to expand reversibly and adiabatically to twice its volume. Its
initial temperature was 25.00◦C . Calculate the change in internal energy and enthalpy for the
expansion process.