Question

Find the missing properties and give the phase of the ammonia, NH₃.

a.  T = 65°C, P = 600 kPa u = ? v = ?

b.  T = 20°C, P = 100 kPa u = ? v = ? x = ?

c.  T = 50°C, v = 0.1185 m³/kg u = ? P = ? x = ?

Answer 1

(a)  P < P_sat => superheated vapor

v = 0.5 × 0.25981 + 0.5 × 0.26888 = 0.2645 m³/kg

u = 0.5 × 1425.7 + 0.5 × 1444.3 = 1435 kJ/kg

(b)  P < P_sat => x = undefined, superheated vapor, v = 1.4153 m³/kg ; u = 1374.5 kJ/kg.

(c) Sup. vap. ( v > v_g)  P = 1200 kPa, x = undefined u = 1383 kJ/kg 

States shown are placed relative to the two-phase region, not to each other.