This worksheet asks students to do basic conversions of mass or molecules to moles and vice versa.
Students combine sodium carbonate and hydrochloric acid generating carbon dioxide gas which is allowed to escape. They measure the actual yield of carbon dioxide produced (missing mass), calculate the theoretical yield using stoichiometry, and then the percent yield. Students understand that 100% yield is the most appropriate answer (based on the Law of Conservation of Mass), so after considering the meaning of significant figures and the uncertainty of their measurements they are asked to decide if they did (or did not) get an answer that might indicate the validity of the Law.
Having completed a unit on stoichiometry, I was looking to review with my HS students some key topics before Spring Break. I had received from FLINN scientific their "It's Elementary--March Madness" activity:
In this Activity, students make their own version of "Fizzies", a carbonated drink product. Students use different combinations of powdered drink mix, citric acid, baking soda, and water to try to create a good-tasting beverage. The Activity enables students to see the practical benefits of stoichiometry when they use it to develop a product they can immediately consume.
In this Activity, students use building-block car kits to explore stoichiometry in a concrete manner. They determine the relationship between the number and mass of each required car component (the pieces in the kit) and the mass of the final product (the completed car). This Activity works well as either an introduction or review of stoichiometry.