There is a traditional stoichiometry lab I have done before. It involves adding dilute hydrochloric acid to sodium bicarbonate, boiling off the fluid and then getting the mass of the sodium chloride. Students then can solve the percent yield for the sodium chloride based on the amount of sodium bicarbonate they use. It is not a bad lab. Something about having hot ceramic watch glasses with acid just makes me a bit nervous. I am not sure where I got this new lab, but it has been one that has evolved over the years It is quick, dirty, relatively simple and uses over the counter (mostly) materials.