Ben Meacham's blog

Using the ACS Exams in Your Classroom

ACS Division of Chemical Education Examinations Institute Logo

Say the words standardized test to most educators and you will likely notice a minor gag reflex. While I completely sympathize with this reaction given the frequently labeled testing culture that’s been far too often forced upon us within the past 15 years, I think it is appropriate to take a step back and recognize the meaningful role a standardized test can have on our curriculum and instruction. After a recent experience using an exam from the ACS Division of Chemical Education Examinations Institute1, I was able to recognize that meaningful role. So, the purpose of this article is to provide useful information for anyone interested in the exam implementation process.

Modeling the Concept of Ionic Bonding

film canisters with different strengths of magnets

When describing abstract concepts like chemical bonding, it always seems to feel far too easy for both teachers and students to resort to the “wants” and “needs” of atoms. After all, we understand what it means to want, need, or like something, so it often feels appropriate (and easier) to use a relatable metaphor or subtly anthropomorphize these atoms to accommodate our students’ current reasoning abilities. While predicting the types of bonds that will form and the general idea behind how atoms bond can be answered correctly using such relatable phrases or ideas, the elephant in the room still in remains—do our students really understand why these atoms bond? 

Shorten Grading Time with this Stoichiometry Tool

Image of a chemistry themed clock

As many chemistry teachers know, grading lab reports can be a very time-consuming task. For me, the lab report that has required the most time to grade is a stoichiometry lab that I have been doing the past couple years. Though we do at least four “formal” lab reports each year, what makes this one different is that it involves a lot more calculations and subsequent results than any of our other labs. Regardless of how well they organized their report or wrote their conclusions, their results need to be checked for accuracy. This takes time. Even after eventually being able to generally eyeball their work, it still takes more time than I would like. So, this year I finally decided to sit down and generate a tool for me to expedite this process—the stoichiometry calculator.

Gas Laws and the Over-Reliance on Algorithmic Thinking

As our Gas Laws unit was coming to an end, it was time to create the test. As I thought of potential test questions that were both challenging and in alignment with the learning objectives we had previously identified for the unit, I was reminded of a multiple-choice question I had been shown in an old Modeling InstructionTM resource.

Investigating the Effect of Concentration on Reaction Time

Concentration vs Rate of Reaction

Whether you are introducing collision theory or something more demanding like reaction order, the reaction between sodium thiosulfate—Na2S2O3 and hydrochloric acid can provide a consistent, accurate, and engaging opportunity for investigating these topics.