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 International Scholastic Journal of Science is an online, open-access journal that provides the opportunity for secondary students to publish entry-level research and become part of the scientific process. In this blog post I will share information about ISJOS and encourage you to find students that are interested in publishing.
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.
If rhubarb stem is placed in a solution of permanganate, the purple permanganate ion is reduced to the colorless Mn2+ ion. It is thought that the oxalic acid present in rhubarb causes this reduction. The investigations presented in this post provide evidence that this may not be the whole story...
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.
A few months ago I was searching the internet, looking for a better way to teach stoichiometry to my pre-AP chemistry students. While my methods of dimensional analysis “got the job done” for most students, I would still always lose students and many lacked true understanding of what was happening in the reaction. I wanted to try something new that would promote a better chemical understanding. In my search for this elusive stoichiometry method, I came across Dena Leggett’s ChemEd X blog post entitled “Doc Save Everyone”, as well as other posts about BCA tables from Lauren Stewart, Lowell Thomson, and Larry Dukerich.
HCl and NaOH, a strong acid - strong base titration? Citric acid and NaOH, a weak, triprotic acid - strong base titration? Do your students standardize the NaOH solution as a first step?