An isothermal displacement calorimeter for the measurement of the enthalpy of solution of gases

The isothermal displacement calorimeter initially described by Stokes, Marsh and Tomlins has been modified to allow the measurement of the enthalpy of solution of gases. This paper reports the enthalpy of solution of argon and nitrogen in tetrachloromethane, cyclohexane, and benzene at 298 · 15 K and the enthalpy of solution of carbon dioxide, methane, ethane, ethene, and propane in the above three solvents at 298·15 and 318·15 K. Comparisons are made with other direct measurements and with results derived from the variation of gas solubility with temperature. The apparatus appears to have a higher precision than those described previously. For carbon dioxide and the hydrocarbon gases the precision is of the order of ±0.2 kJ mol-1, while for argon and nitrogen the precision is of the order of ±0·5 kJ mol-1.