- #1

Jennifer Lyn

- 5

- 0

## Homework Statement

Prove the internal pressure is 0 for an ideal gas and ((n^2)a)/(v^2) for a Van der Waals gas.

## Homework Equations

1. VdQ Eqn: p= (nRT)/(v-b) - ((n^2)a)/(v^2)

2. (partial S/partial V) for constant T = (partial p/partial T) for contant V.

3. dU = TdS - pdV

4. pi sub t (internal pressure) = (partial U/partial V) for constant T

## The Attempt at a Solution

a) Ideal Gas

0 = (partial U/partial V) for const T

int 0 dv = int du

0 = int (TdS - pdV)

int p dv = int T ds

int (nRT/v) dv = int (Pv/nR) dS

nRT x int(1/V) dv = pv/nR x int 1 dS

... and I get kind of lost here, though I know that what I've already done is wrong.. :(

b) VdW gas

I actual have to get going to school, but I'll come back and type up what I've done (incorrectly :( for this part afterwards).