# Homework Help: Entropy calculation help

1. Jan 16, 2006

### cmilho10

A rigid tank of small mass contains 50.0 g of argon, initially at 200°C and 100 kPa. The tank is placed into a reservoir at 0°C and is allowed to cool to thermal equilibrium. Calculate the following:
(a) the volume of the tank
(b) the change in internal energy of the argon
(c) the energy transferred by heat
(d) the change in entropy of the argon
(e) the change in entropy of the constant-temperature bath

I got the volume of the tank from PV=nRT to be 49.2 L which is correct

change in entropy=dQr/T

Change in Eint=Q-W

I'm not sure where to go from here because I do not know how to find the final temperature of the argon.

2. Jan 16, 2006

### fargoth

you stated in your question that you let it cool to 0 degrees.... i think thats the final temprature of the argon...

3. Jan 16, 2006

### cmilho10

It says that the reservoir is at 0 degrees, so I didn't think that would necessarily be the final temperature of the argon cause I thought some of the heat from the argon would be exchanged as well...but maybe I am totally wrong here

4. Jan 16, 2006

### abszero

If it's a thermal reservoir, then the temperature is assumed to remain constant.