Adiabatic Calorimeter for Measuring Heats of Solution at Room Temperature

An adiabatic calorimeter suitable for measurements of heats of solution in the vicinity of room temperature is described. The calorimeter vessel is hermetically sealed and suspended in a vacuum surrounded by a water jacket. The whole assembly is capable of rotation through 180° to initiate the solution process and to stir the contents. Temperatures are measured with a multijunction copper-constantan thermocouple, temperature changes of 10−4°C being detectable. The performance of the calorimeter is illustrated by some results for sodium chloride in water at 25°C. These are in reasonable agreement with the data of other workers and appear to be more self-consistent.