Lab Modules from Dr. Mary Thompson Dept. of Chemistry, College of St. Catherine St. Paul MN 55105

The object of an exercise like NlMBY is to engage future deliberators on what constitutes a case for ethical discussions. Many students are willing to talk about issues related to siting an incinerator or a landfill in their immediate area. The object in this module, however, is to be sure of one's position or of one's opponents position.

As an inquiry-based issue, the definition of each person's position must be based on some solid literature search or visits with people associated with these kinds of problems: landfill management, waste disposal sites, recycling firms; state or city managers of incinerators, pollution control, nuclear power plant fuel storage; and a myriad of modern problems every state, city and municipality face.

A method many of us have found helpful in such an inquiry-based mode is to assign groups of students to a stakeholder group. This approach requires that students see how others view a situation and take a stance which students believe is not acceptable. Seeing how others reach conclusions --from real data and real information -- can cause us all to look differently at others' choices-- be they ethical or merely optional.

The choice of issue is up to the persons who choose to pursue this module and to what is a strong and ethical issue in their own area. Remember that inquiry-based modes should remind us that people view issues from their own stances and their own experience -- and occasionally from a store of information! There are many viewpoints which inform a decision for a given area To explore these and see how many different players there are will be an exercise we may all need as these issues come closer and closer to us in the next few years.

^†Professor of Chemistry, College of St. Catherine: author to which correspondence should be addressed.

This laboratory module requires the student to track two compounds, one known and one unknown, through a variety of analyses. The known compound is pentaamminechlorocobalt(lII) chloride, or [Co(NH₃)₅Cl]C1₂, a coordination compound of cobalt(lII): the student must discover formula of the other by a series of tests. The module relates this analytical problems to questions such as, how do we ever know what the formula is for any such complex? Metal complexes like the one studied are colored and may be used as pigments; in fact. some of the metal-containing pigments of antiquity are still not identified. Not only has a valuable piece of artistic and cultural history been lost in such a case, but also art restorers lack the best methods to restore such pieces, and museums may not be able to distinguish authentic from forged works where the chemistry remains unknown. The analysis of an unknown cobalt complex thus becomes a piece of chemical detective work.

This experiment is appropriate for second semester General Chemistry; at the College of St. Catherine, the module constitutes a part of a second semester synthesis and analysis laboratory for science majors. Other courses for which this experiment is appropriate include an inorganic course or an integrated laboratory course. The experiment requires four 3-hour laboratory periods if students make their own complexes; three if they are prepared for them by the instructor. To determine the formula of the unknown requires time to complete analyses for N. Cl, Co and water, although some analyses can be carried out concurrently.

Necessary equipment and instrumentation include: glassware for Kjeldahl nitrogen analysis, stirring/heating plates and stirring bars, and pH meters capable of being read in the millivolt mode. Digital pH meters are very advantageous, but they are not essential. Teams of three students seem to work well, but the size of teams can be adjusted to fit the size of the class and the availability of instrumentation.
†Professor of Chemistry, College of St. Catherine: author to which correspondence should be addressed.

Those who live in the Rust Belt are daily aware of the ravages of time, water, and salt - as are those who live near the oceans. Electrochemistry ruins our cars, destroys our bicycles, and generally makes life a constant Nernst equation. At the same time we look to electrochemistry for cleaner, safer forms of energy which can have broad uses, from the fuel cells of space shuttles to rechargeable batteries and the tiny batteries in watches and hearing aids.

The first three sections of this laboratory module explore voltaic cells, corrosion, and electrolysis. Topics investigated include the effect of changes in concentration and cell makeup on potential of the voltaic cells, factors affecting the rate of corrosion, methods of preventing corrosion, and identifying the products of electrolysis reactions. The section on corrosion has lots of "real-world" applications. The final section is a team investigation.

The module is appropriate for general chemistry, liberal arts chemistry, or environmental chemistry laboratories. It correlates well with the electrochemistry topics taught towards the end of the second semester in typical general chemistry courses. Plenty of material is included in the module to challenge the better prepared students. This material can be skipped over, and questions related to it may be omitted, in lower-level chemistry laboratory courses; in these classes instructors may want to emphasize the section on corrosion.

The module may be completed in two three-hour labs. Voltaic cells and corrosion are investigated the first week. During the second week students explore electrolysis and do a team investigation.

^†Author to whom correspondence should be addressed.

This experiment is intended to provide students with a hands-on, inquiry-based experiment in kinetics. Organic chemistry relies on mechanism and students who understand some kinetics have a better hope of understanding what a mechanism is and where it comes from -- if they have an experiment which allows them to measure several concentration of reactant dependencies --and also get a feel for the kinds of energies involved in activations. Kinetics and mechanism play a role in every phase of modern chemistry and biology; temperature- dependent reactions occur at every phase of modern life-- including the microwave!

There are numerous options to explore and vary as students begin to study a hydrolysis reaction of a cobalt(III) complex. First, why choose a cobalt complex? Why can we study this reaction by monitoring every fifteen minutes? Could we study this reaction at room temperature? Why do we have to maintain temperatures for three whole hours, and measure every fifteen minutes for three whole hours??? Exploration of choices and results could occupy students and teacher in class as well as laboratory. This is an area where practical experience can provide a context for what feels like a theoretical area and one which can be abstruse and difficult to connect with real, self-collected data Too often we find that clock reactions are used to illustrate kinetics; initial rate methods are the only ones we find illustrations for -- on our text books. Availability of in-laboratory computers or terminals will allow treatment of more sophisticated data and a better grasp of kinetics. Discussion among the groups measuring this experiment under a variety of conditions should lead to a better understanding of mechanism.

This experiment is best completed before or during a discussion of kinetics. It can take from two-three weeks, depending on the nature and number of variations chosen by the instructor and the students. Teams of three persons are best suited to keep order and maintain good technique and data. A week allowed for calculations and discussion is also helpful.
^†Professor of Chemistry, College of St. Catherine: author to which correspondence should be addressed.

Soil analysis is often a mystery to the general public. It is something one should have "done" if plants or vegetables fail to thrive. This laboratory module provides a setting in which students sample soil in flower beds, in woods , around shrubs or trees on campus -- or agree to study and report on faculty or family soil projects. A series of color tests gives a reasonable answer for quick studies, and other qualities of the soil (porosity, salinity, presence of carbonates, organic material, pH) can be determined by relatively unsophisticated means. Students will learn to prepare standards in ppm mode, explained in the experiments themselves, and thus have a better grasp of that elusive term which is ever present in articles about the environment and toxic, or even beneficial, materials. There are no "expected" answers and students will have to determine what is present and what actions to take if recults indicate something is low or missing.

Students can also examine the effects of mulching: if a an area has served as a mulch storage area or if persons choose to mulch one portion of a garden and not another, comparisons can be made on the difference in soil qualities and characteristics. Spring is probably the best time for this module in some parts of the country where soil is not so readily sampled during winter months. The module could take from two to three weeks, depending on the time required to prepare standards and the number of samples to be studied. A group discussion of what the results indicate for "work to be done" in the soil sample.

^†Professor of Chemistry, College of St. Catherine: author to which correspondence should be addressed.

Author Table

General Chemistry Organic Chemistry

Environmental Chemistry Liberal Arts Chemistry

Analytical Chemistry Upper Level Chemistry

Contact Professor Mary Thompson with feedback on her lab modules: Email Dr. Mary Thompson