The Calory and the Joule in Thermodynamics and Thermochemistry

Heats of combustion and formation of the paraffin hydrocarbons at 25 degrees C

“…The at.omic weights of hydrogen, oxygen, and carbon were taken as 1.0080, 16.0000, and 12.010, respectively, from the 1941 table of International Atomic Weights [17].…”

Heats and free energies of formation of the paraffin hydrocarbons, in the gaseous state, to 1,500 degrees K

“…Values of t:,.H.fO 0, the increment in heat content for the reaction of forming the given hydrocarbon in the gaseous state, from the elements carbon (solid, graphite) and hydrogen (gas), with the reactants and the product in their appropriate thermodynamic standard stat.es, at 0° K, were calculated by combining values of t::.. HP298.16 with values of H0298.16-Hoo for the appropriate compounds, by means of the relation 4 (1) where the last t erm on the right is the value of H0298.16-Hoo (the heat content at 25° C less that at 0° K) for 1 mole of the gaseous hydrocarbon less that of n moles of solid carbon (graphite) and (n+ 1) moles of gaseous hydrogen (the molecular formula of the hydrocarbon being CnH 2n+z).…”

“…The unit of energy used in this paper is the conventional thermochemical calorie defined as follows [1].3 1 calorie=4.1833 internatio' nal (NBS) joules.…”

Some experimental data on the heats of combustion of benzoic acid and carbon (graphite)

“…The unit of energy upon which the values reported in this paper are based is the international joule determined by the standards of r esistance (international ohms), electromotive force (international volts), and time (mean solar seconds) maintained at this Bureau [1].…”

“…The data on carbon (graphite) are being utilized in the selection of a new best value for the heat of formation of carbon dioxide [9]. 1 Figures in brackets indicate the literature references at the end of the paper.…”