# Easy Thermo Question

1. Feb 26, 2007

### suspenc3

An Ideal monatomic gas at initial temperature $$T_0$$ (in Kelvins) expands from initial volume $$V_0$$ to volume $$2V_0$$ by each of the 5 processes indicated in the T-V diagram. In which process is the expansion a.)isothermal, b.) isobaric or c.)adiabatic? Explain your answers.
d.) In which process does the entropy of the gas decrease.

So far Ive said that AE is isothermal, initial and final temperatures are the same.

AC is isobaric, Pressure remains constant

AE is adiabatic, no heat flows in or out of the sytem

Is this right?

I dont know what to do for d.)...

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Last edited: Feb 26, 2007
2. Feb 26, 2007

### robb_

huh??? Could you restate the question.

3. Feb 26, 2007

### robb_

wow, sorry. I dont know how that happened? I only hit reply once.

*edit* problem resolved

4. Feb 26, 2007

### turdferguson

Is adiabatic expansion a heating or cooling process?

5. Feb 26, 2007

### suspenc3

See edited original post and Attachment.

6. Feb 27, 2007

### Andrew Mason

I can't see your diagram yet, but I expect there are 3 choices: a horizontal line (T = constant), a curve where T/V = constant and a curve that goes below that (lower final T) where $T/V^{\gamma-1}$ = constant. I think you can determine from that whether your answers are right.
For adiabatic dS = dQ/T = 0. But for the others, which way does the heat flow?

AM

Last edited: Feb 27, 2007
7. Feb 27, 2007