stoichiometry

The Two Words Every Chemistry Student Needs to Learn

student whiteboard using "for every"

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

Stoichiometry resources

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

picture of materials and WS

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

One teacher's attempt to use BCA Tables for Stoichiometry

The thermal decomposition of copper II carbonate basic

In this blog post I'll describe a recent attempt at using BCA Tables for teaching stoichiometry. I discuss the method I used with one introductory chemistry class to teach both the algorithm method and BCA tables to learn more about a technique I've been curious about for a while.

Target labs, Reviews and THAT kid...

It is really hard to get to know THAT kid especially when I have classes of other kids who are important and have needs also. Stack on top of this teenage hormones, spring, nice weather, prom, AP tests, state testing and trying to sell as hard as I can how fun "stoichiometry" is....I now run the risk of turning a bunch of other kids into THAT kid pretty quickly.

Spring Fever, Stoichiometry and Specific Heat

Smore

From the looks of things, we are all in the same boat. Spring fever. I had two groups of students. Both are ending 3rd quarter, looking out a window at the first nice weather we have had in weeks. Most are already planning their spring break vacation and some have left early. Notice, not much talk about chemistry. The curriculum said it was time for stoichiometry for one group and specific heat for another. Just what the kids wanted to do (read with sarcasm).

What is it a student should be able to do and explain? How do we find that out???

mole activity

A perfect storm starts to form. We are on the concept of moles and I have some students who are struggling mathematically. It is a rough time of year to get kids excited. Many students are struggling with ACT and SAT prep and as a teacher, I am tired of test...test...test. Also, I had about two dozen 2 liter bottle "pre forms" that I needed to find something to do with.