Wet the wood splints before disposing of them in the nonhazardous waste container. Collect the unused nitrate solutions for future use in this experiment. Students may have difficulty distinguishing the calcium and strontium color differences. This experiment is designed to replace a similar experiment using barium chloride. Barium chloride is highly toxic and creates a disposal problem.
Magnesium sulfate is essentially nonhazardous and can be flushed down the drain.
Review and demonstrate the proper technique for transferring a crucible and cover and for heating a crucible. The cover must be placed slightly ajar when heating the crucible. Keep the cover on the crucible when it is being cooled to avoid mass transfer. If the lab is split over two days, place the crucibles in a desiccator. Heat the crucible gently during the first five minutes.