Question

A substance is at 300 lbf/in.2, 65 F in a rigid tank. Using only the critical properties can the phase of the mass be determined if the substance is nitrogen, water or propane?

Find state relative to the critical point properties,

(a) Nitrogen 492 lbf/in.2227.2 R

(b) Water 3208 lbf/in.2 1165.1 R

(c) Propane 616 lbf/in.2 665.6 R

Answer 1

| P < Pc | P < Pc | T = 65 F = 65 + 459.67 = 525 R |
| N2 | T >> Tc | Yes gas and P < Pc |
| H2O | T << Tc | P << Pc so you cannot say |
| C3H8 | T < Tc | P < Pc you cannot say |