Ever wonder why some call precipitation reactions "double decomposition". Perhaps (or perhaps not) two (double) salts are sort of splitting apart (decomposing?) and then reforming with other radicals. But a solvent (usually water) is necessary to achieve the desired effect. But is adding water to a salt really decomposition?
I facilitate a working group of chemistry teachers in the New York area and we recently created our own activity surrounding the topic of oxidation. The goal of the probe was to force students to think about what the meaning of oxidation is, as well as to allow students to engage in the science and engineering practice of argumentation. This was an introductory lesson to my oxidation and reduction unit prior to students learning the terms oxidation and reduction.
The author explains how she assigns roles for her students while completing laboratory work. The lab activity is designed to allow students to explore the use of indicators. It serves as an introduction to acids, bases and pH.
Atomic theory is a common topic throughout any introductory chemistry course. It is likely that Rutherford’s gold foil experiment gets at least some attention in your course. I have used a simple activity that gives students an opportunity to replicate Rutherford’s experiment through an analogy experiment that may allow for easier conceptualization of the experiment itself and provide additional support for model development.
Trends related to placement of elements on the periodic table are often taught using diagrams in a textbook. Students often memorize trends, but to get a true grasp of their meaning and what causes certain patterns is best understood when students create their own models and discuss the patterns with others.
A favorite demonstration is to boil water by lowering the pressure in a bell jar using a vacuum pump. Unfortunately, purchasing a bell jar, vacuum plate, and vacuum pump can run upwards of $1,000 which poses a hardship for many teachers. Here are two simple and inexpensive demonstrations of phase equilibrium and vapor pressure.
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.
My first experiment involves measuring the density of water. Each group of two kids is assigned a specific volume of water from 10 to 100 mLs on the tens. They simply measure the mass of an empty graduated cylinder and then add the water and find the mass again. Once they have their data they go around the room and find another group that has one of the volumes that they need and get the data from them and record their names. Once complete they generate a graph of the data and answer a few simple questions. The whole procedure can be completed in about 20 minutes.
A classroom activity to demonstrate the principles of chemical kinetics and equilibria and the utility of the mole concept is described here. The activity involved no hazardous materials or complex equipment and can be enjoyed and appreciated by general studies students as well as chemistry majors.
Students can build their own Hoffman apparatus. An animation of the electrolysis on a particulate level is available to show students before, during or after students perform the electrolysis.