Answer:
1) Sv = 0.4584 m³/Kg...assuming steam as an ideal gas
% deviation from the values in the steam tables
⇒ % dev = 45 %
2) mass air = 272.617 Kg; assuming air to be an ideal gas
Explanation:
ideal gas:
PV = RTn
molar volume:
⇒ V/n = RT/P
∴ P = 90 psi * ( 0.06895 bar/psi ) = 6.2055 bar
∴ T = 650 F = 343.33 °C = 616.33 K
∴ R = 0.08314 bar.L/mol.K
⇒ V/n = (( 0.08314 )*(616.33 K )) / 6.2055 bar
⇒ V/n = 8.2574 L/mol * ( m³/1000L ) = 8.2574 E-3 m³/mol
specific volume ( Sv ):
∴ Mw = 18.01528 g/mol
⇒ Sv = 8.2574 E-3 m³/mol * ( mol / 18.01528 g ) * ( 1000 g/Kg )
⇒ Sv = 0.4584 m³/Kg
steam table:
∴ P = 6.2055 bar ≅ 6 bar → Sv = 0.3157 m³/Kg
⇒ % deviation = (( 0.4584 - 0.3157 ) / 0.3157) * 100
⇒ % dev = 45.2 %; significant value, assuming steam to be a ideal gas
2) mass air, assuming ideal gas:
∴ V = 20ft * 35ft * 10ft = 7000ft³ * ( 28.3168 L/ft³ ) = 198217.6 L
∴ P = 17 psi * ( 0.06895 bar/psi ) = 1.172 bar
∴ T = 75 °F = 23.89 °C = 296.89 K
∴ R = 0.08314 bar.L/K.mol
⇒ n air = PV/RT = (( 1.172 )*( 198217.6 )) / (( 0.08314 )*( 296.89 ))
⇒ n air = 9411.616 mol air
∴ Mw air = 28.966 g/mol
⇒ mass air = 9411.616 mol * ( 28.966 g/mol ) = 272616.892 g = 272.617 Kg
