Research Article

Density and Heat Capacity of Liquids from Speed of Sound

Table 4

The Lagrange polynomial orders used in the subcritical domain.

Substance Interpolation with respect to Derivation with respect to
pTpT

Ar914, 1592, 11
N21014, 15102, 11
CO21014, 15102, 11
CH41414, 15142, 11

Polynomial of 15th degree is used only when the temperature range is extended.
Polynomial of 2nd degree is used for 3 lowest temperatures.
Polynomial of 11th degree is used for 12 highest temperatures.