This experiment requires you to layer two solutions of different densities in a small container as shown below. This is difficult to do without accidentally mixing the two solutions. A special technique can be used to create a layer of the heavier solution beneath a second layer of the less dense solution.

View a video demonstration of the layering technique (11.0 MB)

Over the course of the distillation, samples of the distillate will be collected at various time points. In order to perform a material balance, the composition of these samples must be known. The composition of an ethanol/water solution can be determined if its density and temperature are known. A hydrometer is a tool used to determine the density of a solution. Hold the mouse over the different parts of the hydrometer below. Click on each one to hear a description.