# Homework Help: Thermodynamics specific volume, heat, & ideal gases

1. Sep 11, 2011

### JON123

1. The problem statement, all variables and given/known data

I attached the problems. The first one is D) at the top of the page parts a) and b). The second one is E) at the top of the second attachment.

1) The rigid tanks shown below have volumes of .4m^3 and .004^3 respectively and each contains a water liquid-vapor mixture of mass 2Kg at 50 degrees Celsius. Heat is applied in each tank until the mixture becomes one phase. Note the tanks do not affect each other.

2) On the P-V diagram shown below, for an ideal gas, show three points for which the ratio (V/T) has the same value, and provide full justification.

2. Relevant equations

3. The attempt at a solution

1) The rigid tanks shown below have volumes of .4m^3 and .004^3 respectively and each contains a water liquid-vapor mixture of mass 2Kg at 50 degrees Celsius. Heat is applied in each tank until the mixture becomes one phase. Note the tanks do not affect each other.

a) Find the final phase of water in each tank providing full justification.

I didn’t know how I could solve this mathematically because I don’t have an initial pressure, final pressure, or final temperature. I would just say that the liquid-vapor mixture is heated till it becomes a single phase. The next phase after liquid is a vapor. Therefore the final phase in both tanks is vapor. Would this be valid for my justification in this problem?

b) Show the process in a temperature-specific volume diagram in each case.

I would say each case has a similar graph. The volume is constant so it would just be a straight line, one at .4m^3 and the other at .004m^3, but in specific volume. Would this be correct?

2) On the P-V diagram shown below, for an ideal gas, show three points for which the ratio (V/T) has the same value, and provide full justification.

- I have no idea where to start on this. I know at a constant temperature P1V1=P2V2 so a graph would be linier and downward sloping?

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