Question

Define the principle of corresponding states. Apply the principle to determine the pressure and temperature of 1.0 mole of ammonia that will correspond to 1.0 mole of H2 at 1.0 atm and 25 degrees celsius.

Answer 1

principle of corresponding states -

On comparison, at the same reduced temperature and reduced pressure will have the same compressibility factor and deviation from ideal gas will have of the same degree.

Pressure of H2 P_H2 = 1 atm

Temperature of H2 T_H2 = 25 + 273 = 298 K

Critical pressure of H2, Pc,_H2 = 12.8 atm

Critical Temperature of H2, Tc,_H2 = 33.23 K

Reduced pressure of H2, Pr,_H2 = P_H2/Pc,_H2

= 1/12.8 = 0.078125

Reduced temperature of H2, Tr,_H2 = T_H2/Tc,_H2

= (298)/33.23 = 8.9678

Critical pressure of NH3, Pc,_NH3 = 111.5 atm

Critical Temperature of NH3, Tc,_NH3 = 405.4 K

Reduced pressure of NH3 Pr,_NH3 = 0.078125

P_NH3/Pc,_NH3 = 0.078125

P_NH3 = 0.078125 x 111.5 = 8.71 atm

Reduced temperature of NH3 Tr,_NH3 = 8.9678

T_NH3/Tc,_NH3 = 8.9678

T_NH3 = 8.9678 x 405.4 = 3635.55 K