# Thermodynamics Problem2

1. Oct 25, 2005

### 2Pac

When a system is taken from state i to state f along the path iaf as shown in the figure, it is found that Qiaf = 53.6 cal and Wiaf = 30.5 cal. Along the path ibf, Qibf = 38.0 cal.
If the difference in volume between states i and b is 0.023 m3, what is the pressure dufference betwen states b and f?

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• ###### prob03a.gif
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2. Oct 25, 2005

### 2Pac

I found the work done along the path ibf to be 14.9cal, converted that to J and divided by .023m^3 to get a pressure in PA. converted 30.5 cal to joules and divided by .023m^3 again. subtracted the two... answer is incorrect. so if that isnt the answer how do i go about solving this?

3. Oct 25, 2005

### GCT

you might want to settle down for a minute, none of us can see your diagram at this time.

4. Oct 25, 2005

### 2Pac

diagram looks like this:
PHP:
^
|    a__________________________ f
|     |                          |
|     |                          |
P     |                          |
|     |                          |
|     |__________________________|
|    i                            b
|_____________________________________>
0                        V

5. Oct 26, 2005

### 2Pac

I guess i'll give you another day to help me out.

6. Oct 26, 2005

### GCT

change internal energy is a state function right, would the change in internal energy be equal for iaf and ibf? If so, how can you calculate the change in internal energy, and from this how can you calculate the pressure difference?