Are students reflecting on what their calculated values indicate? This question constantly runs through the minds of chemistry teachers across the country. Recently educators have seen shifts in instruction that promote connections to real-world phenomena using conceptual depth in understanding.
We, as teachers, can see that life is sometimes like this and we care enough about our students that we want to try to prepare them for careers and problems that we can’t even imagine….because we believe that good education can empower people to go further and reach higher than they could ever dream….and maybe the journey we will start together begins with a simple question in which the answer may not seem immediately obvious...and that is O.K….
Recently, I saw this really funny meme on facebook about the creative process. I think it also sums up designing and sustaining students in long term inquiry:
This article describes a three week lesson plan for teaching stoichiometry using an algorithmic method. Two labs (one designed as a laboratory quiz) several cooperative learning exercises, student worksheets and guided instructional frameworks (forcing students to develop good habits in writing measures and doing problem solving) are included. The highlight of the lessons is the "chemistry carol" (based on Felix Mendelssohn's music for "Hark! The Herald Angels Sing") in which students recite a five-step algorithm for completing stoichiometry problems.
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.
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.
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.
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.