Happy December ChemEdX community! On December 2, 2014 I attended the second of three workshops on NGSS (Next Generation Science Standards) through our local ISD (in Kalamazoo County it is known as KRESA).
In a recent contribution to ChemEd X "Stoichiometry is Easy", the author states that he has "vacillated over the years between using an algorithmic method, and an inquiry-based approach to teaching stoichiometry. " I would like to suggest that there is another approach to mastering stoichiometry and that it should precede the algorithmic one: it is the conceptual approach based on a particle model to represent the species involved in chemical reactions.
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.
Last Thursday (11/6/14) I attended a workshop on NGSS through our local RESA (essentially an ISD for the county/region). I’d like to touch on some of the things I took away from this workshop and will post again after the next follow-up workshops in December and March.
This set of three worksheets are intended to be used as collaborative "Guided Instructional Activities" (GIAs). Two students cooperate to complete the steps of a stoichiometry problem, alternately doing parts of the process as they explain what they are doing and evaluate their partner's work.
The three "Guided Instructional Activities" in this activity are three cooperative learning pieces in which students are guided through the process of converting from one unit to moles (or moles to a unit) by the method of "unit analysis" (dimensional analysis). Students alternate steps in the process and evaluate the success of each step.
This worksheet asks students to do basic conversions of mass or molecules to moles and vice versa.
This worksheet is intended to be used as a "Guided Instructional Activity" (GIA). It asks students to find the molar mass of selected elements and write the molar mass as two equivalent fractions ("conversion factors") and as an equality. It is designed to help develop good habits in representing molar mass and other conversion factors, and to emphasize the idea that a conversion factor has a numerator and denominator that "name" identical quantities using different measures.
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.
On September 2, the American Association of Chemistry Teachers (AACT) launched its official website, loaded with lots of resources and member benefits. If you visit teachchemistry.org, you will find many great tools that K–12 teachers of chemistry can use in their classrooms; the new online periodical, Chemistry Solutions; professional development opportunities; and a community for you, in addition to many other benefits.
