NEW VAPOR-PRESSURE EQUATIONS FROM TRIPLE POINT TO CRITICAL-POINT AND A PREDICTIVE PROCEDURE FOR VAPOR-PRESSURE

The quadratic and the cubic equations, previously proposed by us, for the representation of vapor pressure from the triple point to the normal boiling point, have now been extended to the critical point by the addition of two more parameters to each of them. They have been compared with the equations proposed by R. D. Goodwing and W. Wagner. The extended quadratic equation employing only four parameters has been found to represent the vapor pressure of even such a complex substance as water quite adequately.