Did you figure out how the experiment in Chemical Mystery #14 was performed? The solution is presented here!
It can be difficult to engage students in reviewing for semester exams by using worksheets or practicing problems on the whiteboard. If you are looking to change up your review plans, you might consider using a lab activity that provides opportunity to revisit many of the topics that need to be covered.
Recently, my district made a commitment to helping its teachers reflect and rethink their grading and assessment practices. One of the phrases I kept hearing throughout our staff professional development sessions was authentic assessment. I understood (and agreed with) the basic premise—create more opportunities for students to perform tasks that demonstrate meaningful application of essential knowledge and skills. Doing so involves going beyond, or even potentially replacing, traditional summative assessments at the end of each unit.
A solid grasp of proportional thinking is crucial to being able to solve all sorts of problems in chemistry as well as “real life” situations. While many students seem to intuitively understand that one mole is equal to 6.022 x 1023 particles when the analogy is drawn to a dozen eggs, for some, this sort of equality is a puzzling mystery.
A discussion of how students solve stoichiometry problems.
In my class, I use the illustration of a mountain to help students push through the challenges of chemistry. Stoichiometry is the top of chemistry mountain. As we progress through the year, I say things like “the mountain is getting steep here!” or “there is not a lot of oxygen up here!” or “I will carry you up chemistry mountain if I have to!” to keep students motivated. When students finally get to the top of chemistry mountain (mid quarter 3), the air is thin, they are tired and they are ready to base jump off the mountain (see illustration from a former student below).
Inspired by Ben Meacham's post on stoichiometry, I looked to modify the lab sequence for my IB Chemistry class for our unit on stoichiometry. I will describe my experience modifying a typical empirical formula lab, along with using a modified version of the lab Ben shared.
Teaching students the proportional reasoning skills needed for stoich doesn’t have to be that daunting. By adjusting how your students talk about stoich, you will adjust how they think about it; eventually, they’ll proportionally reason in a more effective manner.
This post was submitted for the 2017 ChemEd X Call for Contributions: Creating a Classroom Culture.
In a recent post, I shared sample quiz questions as to how I have differentiated assessment within the mole unit. Here, I share a specific multi-day sequence within the stoichiometry unit. I have written extensively about the project that drives this unit (within the following blog posts: Why consider trying project based learning?, Backwards planning your PBL unit - An Overview of an Entire Unit and What ARE my students actually learning during this long term project (PBL)?), but very little about specific learning tasks. Below is a two day sequence of stoichiometry practice that I set up in my classroom. Stations are set up around the room and students rotate as necessary.
A few months ago I was searching the internet, looking for a better way to teach stoichiometry to my pre-AP chemistry students. While my methods of dimensional analysis “got the job done” for most students, I would still always lose students and many lacked true understanding of what was happening in the reaction. I wanted to try something new that would promote a better chemical understanding. In my search for this elusive stoichiometry method, I came across Dena Leggett’s ChemEd X blog post entitled “Doc Save Everyone”, as well as other posts about BCA tables from Lauren Stewart, Lowell Thomson, and Larry Dukerich.