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Stoichiometry Fireworks Lab Quiz

David Licata | Mon, 11/03/2014 - 21:39

Given the amount of one reactant, students must use stoichiometry to find the ideal amount of the second reagent to use to create purple fireworks. The teacher ignites each groups' fireworks. Ideal mixture create little or no ash. Student assignment sheet with directions (and different initial amounts) plus teacher information and sample answers are included. This is an exciting and engaging activity that can be used as a stoichiometry quiz.

Mass of a Reaction Product

David Licata | Wed, 10/29/2014 - 21:41

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.

Melting Pennies

Tom Kuntzleman | Tue, 08/26/2014 - 13:34

I am fascinated by the chemistry of pennies. I have tried several experiments found in the Journal of Chemical Education.

Floating Squares

Deanna Cullen | Tue, 06/03/2014 - 13:00

I was looking for a new demonstration to initiate a discussion about polarity and related properties to use as part of an exam review. I found a video at ChemEd X (this is part of a ChemEd X subscription). It is entitled “Floating Squares – Hexane and Water” (see note below). I have placed both solutions together before, but I had not added the squares. The demonstration fulfilled my needs. I could have used the original video and muted it if I had not had hexane to demonstrate with.