This post describes a simple way to generate blue, green, orange, and yellow copper complexes, and to use these complexes to introduce students to the effect of temperature on chemical equilibria. The protcol avoids the use of caustic agents, allowing the experiments to be conducted by students as a laboratory-based investigation.
What is the pressure inside a bottle of soda pop? Read this short article to find the surprising answer to this question, and also to learn how to do an experiment to answer this question for yourself!
Solutions of copper (II) dissolved in acetone are easy to prepare, and can display orange, yellow, green, and blue color depending upon conditions. Such solutions allow for a variety of demonstrations and experiments that illustrate principles of chemical equilibrium.
My top 5 reasons for using Green Chemistry in my classroom along with a few examples of replacement labs that follow Green Chemistry principles.
For dynamic equilibrium, I like to use a physical analogy that pits students against each other in a classroom-wide “snowball” fight. Not only is this activity great for building students’ conceptualization of dynamic equilibrium, it is also really fun!
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.
A favorite demonstration is to boil water by lowering the pressure in a bell jar using a vacuum pump. Unfortunately, purchasing a bell jar, vacuum plate, and vacuum pump can run upwards of $1,000 which poses a hardship for many teachers. Here are two simple and inexpensive demonstrations of phase equilibrium and vapor pressure.
I was drawn to an article by Eilks, Gulacar, and Sandoval about Acid-Base Chemistry and Chemical Equilibrium in the April 2018 issue of JCE. The title of the article is "Exploring the Mysterious Substances, X and Y: Challenging Students' Thinking on Acid-Base Chemistry and Chemical Equilibrium." The premise of the article is to demonstrate how an instructor may use a group of compounds (zeolites) to "elaborate on the behavior of solid state acids and bases" while revisiting LeChatelier's principle.
One of my goals for 2017 was to read more chemistry non-fiction. I accomplished that with three and a half books read. That doesn't seem like much, but given how busy I've been lately it was quite an accomplishment! I offer a brief review of my most recent book here, "The Alchemy of Air" by Thomas Hager.
Is it time for us as chemistry teachers to move beyond the Le Châtelier Principle as justification for why disturbances to equilibrium systems cause particular “shifts”? The author shares his new approach to teach equilibrium and provide his students with a more rigorous understanding of the concept.