acid/base

Self-Inflatable Valentine Balloons – Chemistry is Everywhere!

Recently, while attending the High School Teacher Day at the ACS National meeting in New Orleans, we were given Wack-A-Pack™ valentine balloons and encouraged to play with them. I am a huge fan of finding chemistry in the real world and using it as an integral part of my instruction; and as we were experimenting, I was reminded of a rather fun activity I had done on Valentine’s Day with my AP students.

Titration: What do you prefer?

Titrating this year for me has an added complication. The complication is that half of the science department has to be completely packed up and out of our rooms, including chemicals and equipment, before school ends. Half of the department is going to be completely remodeled (my half of course). Teaching must still go on in the middle of the madness.

From JCE - A demonstration for challenging students' thinking on acid-base chemistry and equilibrium

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.

Acid Base Speed Dating

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. 

Soap Making

Heidi Parks offers a soap-making lab or activity that can be run in a chemistry class with 25-30 students working at the same time. She usually does this activity right before spring break, as it provides enough time for the soap to harden and cure (high school students are impatient to use their soaps right away, which you should not do with cold process soap). She has used this soap making activity at different points in the curriculum: during intermolecular forces, during acids and bases, and during stoichiometry. 

Titrations and Microscale Chemistry

I tend to enjoy acid base titrations for several reasons.  First, students get to work with burettes, acids, bases and they see a nice "color change" when they reach an endpoint. Many times, students who tend to struggle with pen and paper testing excel at the "hands-on" approach. Titrations also dovetail well with stoichiometry which provides a nice review of information closer to the end of the year.

Real World Application: Drain Cleaners - Should I use them?

Common drain cleaners consist of water, sodium hypochlorite (bleach) and sodium hydroxide (base) and/or potassium hydroxide (base). Bases are caustic (caustic loosely means to gnaw or eat away at) and can cause corrosion in metal pipes. Wouldn’t you know, our house has PVC piping through the fixtures that dump into a 45 year old cast iron pipe. The cast iron pipe is old and currently shows signs of surface rust and corrosion to the point where the pipe appears to be leaking then sealing itself in several spots. Not to mention the interior of the cast iron pipe may not be completely open, thus, not permitting a fast flow in drainage. Good news: a home warranty is being taken advantage of to hopefully replace the cast iron pipe with a PVC pipe.