One of the problems with many published experiments for the high school level is that they appear as isolated entities in the eyes of the students, having a duration of only one or two class periods and usually connecting to just one or two major concepts in the curriculum. This article describes an experiment that can move beyond this limited function and instead can act as an overarching project, tying together several chemistry concepts. Further, the experiment engages students in synthesizing several different laboratory techniques as they are required to extract, separate, and purify calcium nitrate (from an enriched soil sample) and then convert it into potassium nitrate, which is isolated. As an extension of the main work, students are asked to combine the potassium nitrate generated with the other two ingredients of black powder which can then either be tested for proper burn characteristics or used in a followup experiment. During the course of this multi-week investigation, students will be asked to apply concepts related to separation techniques, intermolecular forces, ionic bonding, qualitative analysis, and solution and oxidation–reduction chemistry. It is a process that will ideally leave them with a sense of the cohesive, interconnected nature of real chemistry.
Supplement
The student version of the project handout, including background, goals, and followup work for all of the components of the project, and the rubric used to evaluate students are available.
The "Chemistry Teacher Connection" (CTC) is especially for high school chemistry teachers. For only $40/year, it offers an online-only subscription to CLIC along with membership in the Division of Chemical Education, normally $65/year. CTC subscribers receive access to all articles and supplements from 1996 through the current issue.
Through special arrangement with the ACS, JCE High School CLIC is now able to provide subscribers with online access to Chemical & Engineering News articles that have been selected specifically for secondary science instructors and their students.
Occasionally, collections of JCE back issues become available for donation to individual teachers, schools, or libraries. JCE matches collections with interested recipients. Recipients pay shipping costs or pick up the collection.
For journals in other fields of chemistry visit ACS Publications.
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