Moles, mole ratios and stoichiometry have been frustrating topics for many of my chemistry students. The MOLE and Avogadro’s number get tangled up in other Chemistry jargon and students have stared at me like I am speaking another language. I have been around long enough to know this is a problem that many of us have faced. I have tried many ideas that have helped and I want to share a few.
I have shared the Target Inquiry Web site previously in other blogs. I have used the Mole Money Lab (written by J. Doug Mandrick) and more recently, the Cookie Conversion Lab (written by Matt LeaTrea) that are both published on that site. (You need to register and request a password, but use of the site is absolutely free.) Both labs allow students to practice converting values from one unit to another using coins (Mole Money) and baking ingredients (Cookie Conversion). I complete these activities after introducing the MOLE concept, but before I get very far into stoichiometry problems. Once we begin completing math problems with chemical equations, I can remind students of the steps they used to convert in those previous activities and guide them to solve the stoichiometry problem.
After introducing STOICHIOMETRY, I use a simulation from PhET called Reactants, Products and Leftovers. I use Trish Loeblein’s Activity 1: Intro to Chemical Reactions and Limiting Reactants and some of her clicker questions as formative assessment items when my students have completed their work. The students build cheese sandwiches before moving on to chemical reactions. I refer to those cheese sandwiches many times as students work to master stoichiometry problems in the following days.
Shout Out to PhET: If you have not used PhET simulations, explore the site right now! PhET provides researched based interactive simulations through the University of Colorado at Boulder. Along with the simulations, you can find an assortment of activities/handouts/ clicker questions and more. Trish Loeblein has posted a list of chemistry simulations she uses throughout the year. I have used and modified other activities that are available on the site, but I know I can depend on Trish’s to be a good fit for my needs. I use the simulations in teacher led discussions, as a student activity or homework and I sometimes incorporate a simulation as part of a lab to help students see what is invisible (at the particulate level). This has been beneficial in developing a deeper understanding and making connections.