Heats of solution of gaseous hydrocarbons in water at 15, 25, and 35°C

Calorimetrically measured heats of solution of eleven hydrocarbon gases into water are reported at 15 and 25°C. Gases studied are methane, ethane, propane, n-butane, 2-methylpropane, 2,2-dimethylpropane, cyclopropane, ethene, propene, 1-butene, and ethyne. These values in combination with previous results are used to derive heat capacity changes at 25°C. Comparison of enthalpy and heat capacity values with those from other studies shows satisfactory agreement. Correlation of the heat capacity change with the number of water molecules in the first solvation shell of the solute suggests that the observed heat capacity changes are primarily due to changes in the water molecules in this solvent shell.