A 12 Lit rigid tank contains 1 kg of saturated liquidvapor m

A 1.2- Lit rigid tank contains 1 kg of saturated liquid-vapor mixture of water at 175 C. The water is now slowly heated until it exits in a single phase. What is the initial pressure? At the final state, will the water be in the liquid phase or the vapor phase? Explain your reason. Show the process on a P-v diagram What is the quality (x) at the initial state?

Solution

From Tables, the saturated vapor at 175C has pressure 114.7psig or 7.912 bar

If you heat slowly, the water gets vaporised to steam.

From pv=nRT, the values are subsstituted and we get n moles of vapor

p= 913.8KPa, V= 1.2 litre, R= 8.314, T =448K

n = .294 moles, or 5.3 Kg of gas is possible, if 1kg is originally there, total gas is possible