In two connected ways, thermodynamics describes how both physical or chemical processes spontaneously trend towards equilibrium. This post is concerned with showing how free energy (ΔGrxn) changes as the reaction quotient (Q) changes as both trend towards the special condition, equilibrium, described by the constant K.
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.
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.
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.
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.
A classroom activity to demonstrate the principles of chemical kinetics and equilibria and the utility of the mole concept is described here. The activity involved no hazardous materials or complex equipment and can be enjoyed and appreciated by general studies students as well as chemistry majors.
This activity was submitted for a 2016 ChemEd X Call for Contributions soliciting input regarding the big ideas being put forth by organizations like AP. The author shares a lab activity that relies on connections - between stoichiometry, esterification, equilibrium, kinetics, titrations and uncertainty of calculations. He also shares the resources he created.
Throughout the last ten years teaching both chemistry and Advanced Placement Chemistry I have realized that the concept of equilibrium does not receive enough attention in my first-year chemistry course. Sure, the concept of equilibrium is a topic mentioned and identified throughout the course however the dialogue in regards to conditions that would shift the chemical system is minimal at best.
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 students, into the extensive use of the BCA approach in AP and
