A piston-cylinder device initially contains 1.4 kg saturated liquid water at tem

Question

A piston-cylinder device initially contains 1.4 kg saturated liquid water at temperature 200C. Now heat is transferred to the water until the volume quadruples and the cylinder contains saturated vapor only. Determine a) the volume of the tank, b) the final temperature and pressure, and c) the internal energy change of the water.

So i know how to solve this problem for my final volume i got .0064792 the only thing that mest me up is when i got to part b) in the book solution, the person was using the saturated liquid table A-4 to find the temperature and pressure. I dont know why that person did that because in this phase we are trying to find the final temperature, the problems states its final phase is saturated vapor so i assumed i should use table A-6 since its a superheated table and used the 35 mpa chart because the values between the temperatures 425- 450 celcius were the closest to the specifice volume which was .004628 so i used linear interpolation and got the value of the final temperature as 444.6 but this whole half of the problems cant be right unless the right table is used so i need someone to explain why they used the saturated liquid chart instead of the super heated chart.

I have an assumption that when you say it is a vapor you might as well consider it to be a saturated liquid? Otherwise i have no clue why they did what they did, please explain i will rate you full stars.

Thank You

Explanation / Answer

because in part b he found the value of x2 which is equal to 1 mean the phase exist ob=n saturated line. if it should be grater than 1 than it will be in super heated and if less than one than in liquid vapor phase or under the curve. but because x or dryness fraction=1 so it will be in saturated or gaseous phase on the line.

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