Convenient nomographic charts are presented that permit determining changes in enthalpy for various processes; namely, compression, combustion at constant pressure, expansion, and heat exchange. Properties presented are enthalpy and and specific heat at constant pressure divided by temperature for temperatures 300 to 3500 degrees R, hydrogen-carbon ratios from 0.10 to 0.20, and fuel-air ratios from zero to stoichiometric. Effects of pressure and dissociation are considered negligible.