Water properties calculations

[physea]

Homework Statement

1kg of water fills 151.1L of rigid container at pressure 2MPa. Then the container is cooled to 40C. What is the final pressure?

Homework Equations

Steam table properties.

The Attempt at a Solution

How can we know the pressure?
I think it is wrong to assume that the specific volume at 40C is the same with the specific volume at 2MPa. Any hint?

 

[Chestermiller]

Homework Statement

1kg of water fills 151.1L of rigid container at pressure 2MPa. Then the container is cooled to 40C. What is the final pressure?

Homework Equations

Steam table properties.

The Attempt at a Solution

How can we know the pressure?
I think it is wrong to assume that the specific volume at 40C is the same with the specific volume at 2MPa. Any hint?

What is the specific volume of the water in the initial state? Here's a hint: In the final state, you will have a combination of liquid water and water vapor, having the same average specific volume as in the initial state. The final pressure should be easy to get, because the system will be saturated.