- A steel tank containing 0
_{2}is heated - slightly., As it is heated, the density of the O_{2}gas- a increases
- decreases
- stays the same? Explain where the heat goes.

- A container fitted with a piston containing 0
_{2}is heated slightly. As it is heated, the density of the O_{2}gas- increases
- decreases
- stays the same?

- What is work?
- How is, it defined for an expanding gas?

Compressing gas?

What is the equation for work for a gas?

Why are each of the terms necessary?

- How is, it defined for an expanding gas?
- Explain why the "foamy stuff" that comes out of a fire extinguisher is cold.

- In Dr. Yerkes demonstration with the dry ice in a sealed bag, the bag expanded, doing PV work. Where did the energy for this work come from?

- A gas absorbs 100 J of heat and is simultaneously compressed by an external pressure of 1.5 atm from 8.0 L to 2.0 L in volume. What is δE for the gas?

- Do #10 in your syllabus. In addition, answer these questions.
- How much work is done?

How much heat is transferred?

- How much work is done?
- Now redo #10, this time using an external pressure of 1.00 atm.
- How much work is done?

How much heat is transferred?

What is the change in internal energy?

- How much work is done?
- In a system where 4 L of gaseous reactant produces 3.5 L of gaseous products, the surroundings have to work on the system because
- the surroundings have to drive the reaction
- the change in volume requires the surroundings to do work by compressing the system
- the reaction is actually doing work on the surroundings by decreasing the pressure
- the volume change in the system has no bearing on the work the surroundings does on the system

- You initially have a gas at P=3.0 atm and V=5.5 L. The gas is contained in a piston with an external pressure such that the final volume is 10.5 L. Calculate the work. Be sure that the sign for work is correct.

- You have the same conditions as in the question above but you go about getting to the final state in two steps. The first step is a volume of 7.0 L. The second step gets you to a volume of 10.5 L. Calculate the total work done in this case.

- Again, you have the same initial and final conditions but this time you expand the gas in two steps with the middle step being at 8.0 L. What is the work?

- In questions 10, 11. and 12 the work calculated is different for each condition. Why isn't work a state function? Why does work increase with the number of steps? Which two-step process yielded more work? Why is this? When is
^{P}external=^{P}internal (answer for both the reversible and irreversible cases)?