Question

A piston-cylinder device initially contains water liquid-vapor mixture at the pressure of 700 kPa. The liquid-vapor mixture has 0.1 m3 of liquid water and 0.9 m3 of water vapor. Heat is transferred at constant pressure until the temperature reaches 320 °C. (a) What is the initial temperature of the water

Answer 1

Given question is incomplete. The complete question is as follows.

A piston-cylinder device initially contains water liquid-vapor mixture at the pressure of 700 kPa. The liquid-vapor mixture has 0.1 m3 of liquid water and 0.9 m3 of water vapor. Heat is transferred at constant pressure until the temperature reaches 320 °C.

(a) What is the initial temperature of the water.

(b) Determine the total mass of the water.

Step-by-step explanation:

(a) We are given that initially there are two phase regions present.

Initial temperature = saturation temperature at 700 Kpa

=
`165^(o)C`

Hence, the initial temperature of the water is
`165^(o)C`.

(b) At 700 Kpa, the saturation pressure will be as follows.

`v_(f) = 1.108 * 10^(-3) m^(3)/kg`

`v_(g) = 0.273 m^(3)/kg`

So,
`m_(f) = (0.1)/(1.108 * 10^(-3))`

= 90.25 kg

`m_(g) = (0.9)/(0.273)`

= 3.3 kg

Therefore, total mass will be calculated as follows.

90.25 kg + 3.3 kg

= 93.55 kg

Hence, total mass of the water is 93.55 kg.