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Heat capacity of gaseous carbon dioxide

1952; US government; Volume: 48; Issue: 3 Linguagem: Inglês

10.6028/jres.048.025

2376-5305

Joseph F. Masi, B. Petkof,

Chemical Thermodynamics and Molecular Structure

The heat capacity (Cv) of gaseo us carbon d ioxide has been measured at -30°, 0°, + 50°, and + 90 ° C and at 0.5-, 1.0-, and lo5-atmosphere pressure, with an accuracy of 0.1 percent.The flow calorimeter used was a modification of the one previously described by Scott and Mellors [1 ] 2 andWacker , Cheney, andScott [2] .In order to test the accuracy of t he calorimeter, the heat capacity of oxygen was measured at 1 atm osphere at -30°, 0°, and + 50°C.Thc measured values of Cv for oxygen were combined with an equation of sta te to gi ve C;; these differed from the statistically calculated values by + 0.03, -0.06 and -0.01 per cent at the three temperatures.The experimental values of Cv for carbon dioxide have been used to calculate new values of C; and values of t he pressure coefficient of heat capacity at the four temperatures of m easu rement.The theoretical values of C; calculated in 1949 [8] were found to be too low by 0.2 to 0.3 percent ; the results of a new calculation are in substantial agreement with the experiments.The press ure coefficients are in agreement with those obtained from the recent pressure-volume-temperature work of MacCormack and Schneider [7].