Investigation of Intermolecular Interactions by Determination of the Heat of Mixing of Organic Liquids

In a hypothesis-based experiment students consider the structure of several common organic solvents and predict whether the mixing of each pair is going to be an exothermic or an endothermic process based on the types of intermolecular interactions present in each. Next, they test their predictions by monitoring the temperature change in the course of the actual mixing. Most students correctly predicted the outcomes of the individual experiments with an exception of toluene, which they treated as a typical non-polar compound.