where M is the molecular weight of hydrocarbon. This relation is valid for n-alkane hydrocarbons and reproduces original data with AAD of 0.28%. Values of scaling factor calculated from Eq.(6) and a comparison with the original data (calculated from PR EOS)is
shown in Fig.5 . Critical properties for pure hydrocarbons used in this study are given in Table 8. Experimental data on the speed of sound used in this work was obtained from open literture for liquid hydrocarbon systems as given in Table 9.