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high school chemistry

Capturing the Beauty of Chemistry with an iPad

Lowell Thomson | Mon, 02/22/2016 - 16:38

In my IB Chemistry class, my seniors were finishing up independent investigations for their Internal Assessment a few weeks ago when something cool happened. One of my students was using silver nitrate and potassium chromate for a titration. This is notable to the story here because the endpoint is marked by the formation of silver chromate as a precipitate, with a deep reddish color. I overhead the student showing his reaction to another student, with both of them commenting on the cool colors involved.

Lewis Take II and Density????

Chad Husting | Sun, 02/21/2016 - 16:06

  First, I would like to thank all those who commented on my last blog. For the record, I was wrong. Initially I looked at Linus Paulings early papers as he worked on electronegativity. Much of the work focused on connecting the concept to bond energy. There were some great comments posted to the blog. Probably one of the best was explaining how the concept of electronegativity presents a model for bonds. It is not an observable quantity. This really helped me explain it better to my students. As the commentor posted, all models have limitations. Second, the person commented that in Linus Pauling's General Chemistry book published in 1970 (Dover Publishing) that he does indeed talk about the differences in electronegativity to discuss a type of ionic and covalent character. I stand corrected.

Toward roads that de-ice themselves

Dan Meyers | Sun, 02/21/2016 - 14:37

This year in the midwest United States, winter has been a fickle friend. I haven’t seen the same amount of snow or ice as in recent years, but I still made sure I was prepared for it at our home by stocking up on calcium chloride to use as a de-icer on my driveway and sidewalks. 

Colligative Properties in Real Life

Dan Meyers | Sat, 02/20/2016 - 10:51

This year in the midwest United States, winter has been a fickle friend. I haven’t seen the same amount of snow or ice as in recent years, but I still made sure I was prepared for it at our home. I went to my local big box hardware store in December and contemplated buying rock salt (NaCl), and NaCl/calcium chloride mixture, or just calcium chloride. Growing up my dad had switched entirely to calcium chloride because it was less damaging to the brick pavers leading to our porch and backyard. In fact, calcium chloride is generally much safer toward plants and soil than NaCl. Even though calcium chloride is much more expensive than rock salt (it was about twice the cost for 10 pounds more), that what’s I chose. Why?

Building Atoms: One App at a Time

Doug Ragan | Tue, 02/16/2016 - 23:42

In my high school chemistry class, a unit we cover is that of atomic structure. In particular, given an elements symbol, mass number, atomic number, and charge, the objective would be for the student to determine the atoms number of protons, neutrons, and electrons. I have several apps/program suggestions that can be useful for this purpose.

Integrating Three Types of Chemical Representation

Erica Posthuma | Mon, 02/08/2016 - 15:40

This past summer our conversations turned to, “How can we improve our instruction to try and prevent the initial misunderstanding?” We had all read Dorothy Gabel’s article Improving Teaching and Learning Through Chemistry Education Research: A Look to the Future. We were intrigued by the author's description of the three fold system of representing concepts in chemistry.

 

Rethinking Stoichiometry

Lauren Stewart | Wed, 02/03/2016 - 12:29

Stoichiometry is arguably one of the most difficult concepts for students to grasp in a general chemistry class. Stoichiometry requires students to synthesize their knowledge of moles, balanced equations and proportional reasoning to describe a process that is too small to see. Many times teachers default to an algorithmic approach to solving stoichiometry problems, which may prevent students from gaining a full conceptual understanding of the reaction they are describing. 

Using "Chemical Detectives" iPad App to Practice Spectroscopy

Lowell Thomson | Fri, 01/29/2016 - 21:46

The new IB curriculum includes compound identification using NMR, IR and Mass spectroscopy. My current high school lab does not have any of these available. And that's no surprise, given the cost of these machines is far out of our budget. And while some of you may be lucky enough to have a connection to a local university or college, for the rest of us what are the options when it comes to teaching spectroscopy?

 

The Search for the Final Element

Tom Kuntzleman | Thu, 01/28/2016 - 19:33

Have you ever wondered what is the theoretically largest possible value for the atomic number of an element? Using some introductory physics and algebra, you can get your students thinking about this idea.