Table 70 289 



THERMODYNAMIC CONSTANTS 



Basic constants: * 

 Apparent molecular weight of dry air, M. 



M — 28.966 



Absolute temperature of the ice point, To. 



To = 273.16 °K. 



Energy equivalent of the International Steam Table calorie (ITcal.) and the 15 C C. 

 water calorie (cal.u)- (Also see Table 1). 



1 ITcal. = 4.18684 X10 T ergs 



= -^tt. -nr, mean International kilowatt-hours 



860 X 10 3 



1 ITcal. = 1.00032 caU 

 Gas constant, R*, for 1 gram mol of ideal gas. 



R* = 8.31436 X 10 T erg. mol" 1 "K." 1 

 = 1.98583 ITcal. mol" 1 'K; 1 

 Gas constant, R, for 1 gram of dry air. 



R = 2.8704 X 10 e erg g." 1 °K.- 1 

 = 6.8557 X 10- 2 ITcal. g." 1 K. J 

 Molecular weight, M v , of water vapor. 



M* = 18.0160 

 Gas constant, R v , for 1 gram of water vapor. 



R. = 4.6150 X 10 9 erg g." 1 'K." 1 

 = 1.10226 X lO" 1 ITcal. g." 1 K.- J 

 Specific heats: 2 

 Dry air, 



difference, c pv — c«« 



'I. M. O. Twelfth Conference of Directors, Resolution 164, Washington, 1948. 

 ■I. M. O. Aerological Commission, Doc. 71, app. IV, Toronto, 1948. 



SMITHSONIAN METEOROLOGICAL TABLES 



