4 October 2002

My Friday night chemistry class is enjoyable for many reasons... Tonight we did a detective-like experiment in which the students analyzed a ternary mixture consisting of sand, salt, and ammonium chloride (another kind of salt). Their job was to determine the percentages of each component in the mixture. First, they heat the mixture (shown here) to cause the ammonium chloride to sublime. Then they add water to the residue and filter it. The salt dissolves and passes through the filter, while the sand stays behind. By weighing things cafefully at appropriate points in the experiment, they can easily determine the composition.

DWL