Question

A 500-m^3 rigid tank is filled with saturated liquid-vapor mixture of water at 200 kPa. If 20% of the mass is liquid and the 80% of the mass is vapor, the total mass in the tank is: (a) 635 kg (b) 2809 kg (c) 258 kg (d) 500 kg (e) 705 kg

Answer 1

(a) 705 kg

Step-by-step explanation:

it is given that volume =500
`m^3`

pressure = 200 kPa

it is given that 80% mass is vapor so dryness fraction =x=0.8

from the standard table at 200 kPa

`v_f=0.001061 (m^3)/(kg)`

`v_g=0.88578(m^3)/(kg)`

specific volume
`v=v_f+x\left ( v_g-v_f \right )`

`v=0.00106+0.8\left ( 0.88578-0.00106 \right )=0.7088(m^3)/(kg)`

we know that
`specific\ volume =(volume)/(mass)`

`0.7088=(500)/(mass)`

`mass=(500)/(0.7088)=705.456 \ kg`