# Homework Help: Isothermal Expansion, No Calculus

1. Aug 25, 2010

### Alexandra_H

1. The problem statement, all variables and given/known data

"We have some gas in a container at high pressure. The volume of the container is 444 cm^3. The pressure of the gas is 2.52e5 Pa. We allow the gas to expand at constant temperature until its pressure equals atmospheric pressure, which is 0.857e5 Pa."

A. Find the work (J) done on the gas.
B. Find the change of internal energy (J) of the gas.
C. Find the amount of heat (J) done on the gas.

2. Relevant equations

First law of thermodynamics. Ideal gas laws.

3. The attempt at a solution

(A) is what I'm having trouble with. The class is not calculus-based. (B) is zero, and for (C), W = Q (appropriate signs, - and -, as they seem to be referencing the surroundings, not the gas itself)--easy enough, once I have A.

Thoughts?
Thanks!

2. Aug 25, 2010

### rock.freak667

Since you can't use calculus to derive the formula, I think you'd just need to use the direct result:

W=PVln(V2/V1)