acids/bases

The disappearing rainbow¹ is a wonderful chemistry demonstration previously featured here on ChemEdX.^2-4 In this experiment, a colorless solution of NaOH is poured into a row of flasks, each containing a different acid–base indicator.

Dean Campbell*, Ali Patel, Kathryn Campbell *Bradley University, Peoria, Illinois

Josh Kenney, Melissa Hemling, and I just published an article in the October 2024 Journal of Chemical Education. The article describes inquiry-based activities that highlight the chemistry behind “No-Mess” picture-coloring books.¹ Well, it turns out that our timing is impeccable.

Phenolphthalein has been used extensively as a pH indicator.¹ Although the compound actually can exhibit multiple color transitions, it is best known for turning from colorless to pink in aqueous solution as the pH is raised above 8.3.¹ The equilibrium associated with this transition is shown in Figure 1.

As educators, we are always looking for ways to make complex concepts more accessible and memorable. In the early 2000s, I attended the Biennial Conference on Chemical Education (BCCE), where I learned about a brilliant brain break activity from renowned chemistry teacher Lee Marek.

Gentle Reader, forgive me if the title - Connecting Acid-Base and Redox Connections (CABARC) - is redundant, but the connections between acid-base and redox reactions already exist, and it is my hope that we as instructors can parlay these connections into easier, better, and deeper understanding of both topics.

Co-Authored by Dean J. Campbell* and Ali Patel* *Bradley University, Peoria, Illinois

I’m always looking for safer and cheaper options to perform chemical demonstrations, and I recently discovered a line of Elmer’s Glue products that support this pursuit. I shared three demonstrations using three Elmer glue products during the ChemEd X Demos Symposium at ChemEd 2023.

Co-Authored by Rhiannon Davids* and Dean J. Campbell* *Bradley University, Peoria, Illinois

An experiment that has always fascinated me is observing what happens when CO₂ is bubbled into limewater (which is a saturated solution of calcium hydroxide).^1-2 This experiment can be carried out by blowing bubbles of exhaled breath (which contains roughly 4% CO₂)³ through a straw into limewater.