How do you demonstrate how a buffer system works? I did some brainstorming, devised a plan and it went well. This post is a description of what I did.
Looking to change up your titration lab? Citric acid is very common in candy and other foods. Students will be engaged in using titration to find the amount of the acid in Mentos Now or other candy. Student and teacher documents are provided to help you use the activity with your own students.
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.
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.
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.
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.
I try to examine activities an multiple levels. First on the list, I want to know if my students will be engaged and learn something. Second, how difficult is it for me as a teacher to actually pull it off? One of the most important questions...are the students learning chemistry or just having fun? This is the first year I have attempted the following activity. Students were engaged in the real world connection, they asked questions, it transitioned into some chemistry concepts and even some parents got involved. The activity involved acid, bases, pH and food.
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.
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.
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