The solution to "Chemical Mystery #16: A Red, White, and Blue Chemistry Trick for You!" is presented. How this experiment can be used as a springboard to carry out a simple quantitative analysis of salt solubility is also discussed.
Science Practice: Using Mathematics and Computational Thinking
This lab is one of my favorite activities to do in my classes and I look forward to it every year. The lab is simple, requires limited supplies, students love it (i.e. high engagement level), and I have found it to really set students up for stoichiometry.
We all know how fundamental the mole concept is for stoichiometry. This year I brainstormed ways to really make it stick. I decided to do multiple mini-practicums, one for each learning target of the mole unit. I am sharing brief descriptions of the mini-practicums I did for each learning target.
The unit of acids and bases is difficult for most students in Advanced Placement Chemistry. The variety of various calculations can be overwhelming. The Acid Base Speed Dating Activity engages students in completing a series of problems. Each student is assigned a specific solution and then determines their individual pH to complete their personal “Solution Biography.” Then the speed dating begins! For each date, the students need to find a specific match and determine their combined pH value.
In this activity, students can look inside the model that resembles the atom and find information that reinforces what an isotope actually is. Furthermore, the quantitative data forces students to examine beliefs about different types of averages and what the numbers really mean. This takes a bit of effort to set up but is inexpensive and can be used year after year.
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.
I taught my students how to use the method of initial rates. I taught my students rate laws. However, they strugged to differentiate when to use what method. Upon further probing, they struggled to articulate why one might use one method over the other. They could parrot back some ideas ("The rate law tells you about the particles involved in the rate determining step of the reaction."), but I wasn't convinced of mastery and connections.
I recently stumbled across a blog about the use of BCA (Before Change After) tables for stoichiometry written by Lowell Thomson. I was thrilled to discover ChemEd Xchange! I wanted to share my journey, spurred on by my s
Each spring my Local Section of The American Chemical Society (ACS) hosts a rigorous two part exam as part of the selection process for the The International Chemistry Olympiad (IChO). The lab practicals on the exams are presented as problems. No procedure is given. Students must use their chemistry knowledge and lab experience to devise a plan and solve the problem. The best part is that the released exams come with lists of materials and equipment, helpful hints to the proctors, and solutions! This is a great source for Inquiry-Based Lab Practicals.
Stoichiometry is arguably one of the most difficult concepts for students to grasp in a general chemistry class. Stoichiometry requires students to synthesize their knowledge of moles, balanced equations and proportional reasoning to describe a process that is too small to see. Many times teachers default to an algorithmic approach to solving stoichiometry problems, which may prevent students from gaining a full conceptual understanding of the reaction they are describing.