Some Like it Hot

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).

The Two Words Every Chemistry Student Needs to Learn

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.

Increasing Access to Stoichiometry Through Differentiated In-Class Practice

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.

Time required: 

POGIL: ~1 hour

Lecture: ~30 minutes

Mastery check, differentiated practice, project planning: ~2 hours

Using Visual BCA Tables to Teach Limiting Reactants

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. 

Moles, Formative Assessment and Moving Forward....

Formative assessment can be a double edged sword. It can be and often is extremely helpful. Some quick short three or four well worded questions at the beginning of a unit provides information about student abilities. A teacher can skip teaching information that kids already know or the teacher can discover concepts that he or she assumed students know but do not. Formative assessment about "Moles" can provide data that is hard to deal with. Can the students handle scientific notation? How well are students at basic math skills?

Titration of an Esterification Reaction to Determine Equilibrium Constant

ChemEd X recently made a Call for Contributions soliciting input regarding the big ideas being put forth by organizations like AP. The first thing that came to mind was a lab I modified that is centered around making connections between topics. Admittedly, this lab is not a "big idea" per se. Rather, it's the big idea that students should be able to make connections between topics we study to solve problems. So in this blog post, I would like to share a lab activity that relies on these connections - between stoichiometry, esterification, equilibrium, kinetics, titrations and uncertainty of calculations. I will also share the resources I have created to support my students through the process of working through these calculations.

Time required: 

Three class periods

Day 1: setup of equilibrium mixture; roughly 30 minutes

Day 2: titration of equilibrium mixture (approximately 1 week after Day 1); roughly 60 minutes

Day 3: calculations; variable time required - typically 30-90 minutes depending on the student group