Question

A piston-cylinder device contains 0.005 m3 of liquid water and 0.9 m3 of water vapor in equilibrium at 600 kPa. Heat is transferred at constant pressure until the temperature reaches 200°C. What is the final volume of the water in the device?

1) 0.005 m3
2) 0.9 m3
3) Cannot be determined without additional information
4) Other

Answer 1

Without additional information like the phase diagram of water or steam tables, it is not possible to determine the exact final volume of water in the piston-cylinder device after heating to 200°C at a constant pressure of 600 kPa.

Step-by-step explanation:

The student has asked about the final volume of water in a piston-cylinder device after heating liquid water and water vapor in equilibrium at a pressure of 600 kPa until the temperature reaches 200°C. To solve this, we require the phase diagram of water or steam tables to determine the specific volumes of water and water vapor at the given conditions because the volume of water changes with temperature and pressure. Without this additional information or steam tables, it is not possible to provide a precise answer to the volume after heating. We know that as the temperature increases, the liquid water will expand and possibly fully vaporize, which would increase the volume occupied by the water vapor. However, under constant pressure conditions, the total final volume can be significantly different from the initial separate volumes of liquid and vapor. Thus, if we don't have the specific volume data at the final temperature (which is assumed to be at the same pressure), we cannot determine the final volume accurately.