The application of Hess's Law frequently presents students with conceptual problems. This series of experiments confirms Hess's Law and offers a robust understanding of this principle. This can be done as a demo completed by the teacher or as a lab with groups of students.
Before trying to use a piece of equipment, it’s worthwhile to have a basic understanding of how it works. To put it simply, FLIR cameras primarily deal with the infrared part of the EMR spectrum. The camera detects infrared energy and converts it into an electrical signal, which is then processed to produce a thermal image on a video monitor.
The post-Thanksgiving excessive calorie-consumption 'blues' have arrived. How is it possible to eat so much? For a bear, it's easy. Easy as pie. Bears are champion eaters, spending about half the year eating non-stop in preparation for winter's foodless landscape. How can this calorie consumption observation about the bear world be used to teach certain chemistry concepts routinely covered? This post includes discussion and two classroom activities about the following common general chemistry topics/concepts- thermochemistry, unit conversions, and interpretation of numerical data. Enjoy...
A common topic in chemistry discussion groups and forums is about the use of the terms “spontaneous reaction” versus “thermodynamic favorability”. This is a new activity for chemistry students who struggle with the correlation between changes in enthalpy, temperature, entropy, and the Gibbs free energy of a system; which relies on an analogy that most students will be familiar with.
If you are looking to go beyond using traditional, arguably misleading, definitions of entropy involving “disorder” and “messy bedroom” analogies, the Boltzmann Bucks game fits the bill. The game, pulled from a Journal of Chemical Education article, provides a wonderful opportunity for students to more accurately conceptualize entropy.
You are likely aware that diamonds are converted - albeit slowly - to graphite under normal conditions. Thus, diamonds don't last forever, in contrast to the popular advertising slogan. However, did you know that you can use chemistry to prove that diamonds are not forever? It's simpler than you think...
The solution to Chemical Mystery #11, which involves the Leidenfrost Effect, is presented.
In Chemical Mystery #10, plastic straws are observed to “magically” change color when waved in the air. Check out the explanation and the video.
As part of a two-week Chemistry Modeling Workshop™ in Houston, TX, I had the opportunity to read the Journal of Chemical Education article “When Atoms Want” by Vicente Talanquer of the University of Arizona. I researched Dr. Talanquer and discovered he created a collection of simulations called Chemical Thinking Interactives (CTI). These digital tools illustrate many chemistry topics with a focus on the particulate nature of matter.
I found a version of this demonstration online a couple of years ago. I admit, when I first tried it with my class it was mostly for a crowd pleaser to demonstrate the activity series of metals, but I then became very intrigued by the processes occurring. The original source only referenced the “single replacement reaction” between Mg(s) and AgNO3(aq). Therefore, when I saw a grayish product (silver) I was not surprised. However, I was surprised by the white flash and the production of a white product, which were reminiscent of the classic combustion of magnesium demonstration. This led to some research and my conclusions that follow. Read through to the end and you will find a video of the demo.