# Homework Help: Thermodynamcics quesstion (Diagrams)

1. Jan 22, 2010

### Macclourin

In a question He gives that :

0.1 kg of water contained in cylinder-piston device .
Water is initially at 1.5 bar and 403 k (Kelvin).
More 0.1 kg of water at 2 bar and 403 kelvin is admitted to the cylinder.
Through out this filling process, pressure and temperature of cylinder are maintained constant.

Represent this filling process on p-v and T-s diagrams

The confusion is how to represent a process at which both pressure and temperature are constant

2. Jan 22, 2010

### fluidistic

Hi and welcome to PF!
Use the relation PV=nRT. If you keep P and T constant while increasing n, V must increase in the same proportion than n.
Also, what is a T-s diagram? Temperature - seconds?

3. Jan 22, 2010

### Macclourin

First : Thank you for your speedy response

Second : I mean that in p-v diagram
horizontal line represents constant pressure
but constant temperature process is represented by a curve
So how to represent a process combining the two conditions ( P and T are constants ) !!!!
Would it be a curve or horizontal line or neither of therm ??

Third : T-S is Temperature -Entropy Diagram .

4. Jan 22, 2010

### fluidistic

Here is what I would do (I could be wrong though).
Use PV=nRT. P, T and R are constants. n increases until it reaches its double value. What can you say about V?
Plotting this in a P-V diagram should not be a problem once you've figured out the previous question.