Lesson List
Aluminum Adventure
Dental Chemistry Analogy
Environmental Concerns
Fatty Acids for Soap Making
Gas Law Investigation
Gasoline Additive
Hydrogen Peroxide Analysis
Programing the "Rinse Robot"
Quality Control at Kality Krunchers Dill Pickle Factory
Real-World Projects: Challenges From the Polymer Industry
Sorting Plastics for Recycling
The Art of Soap Making
The Floating Egg Problem
The Visible Spectrocopy Expert Witness Problem
Using the Spectrometer to Analyze a Mixture
Lesson Descriptions
Students observe an electrochemical cell constructed with pieces of aluminum that serve as both the anode and cathode. Students then determine what effect an organic dye (Rit® brand dye) has on aluminum that has been anodized for 5, 10, or 15 minutes. They also investigate the effects of heating an anodized aluminum strip before treatment with the dye bath. Finally, students use their accumulated knowledge of the anodizing process to design and treat an art object.
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Dental Chemistry Analogy
To investigate the effects of fluoride treatment on teeth, students design a procedure using sodium fluoride and marble chips or eggshells.
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Environmental Concerns
These open-ended projects involve students in multi-week explorations. Students can choose one of two real-world problems and then develop and implement a plan to address their problem. The plan will be based on standard methods and available equipment.
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Fatty Acids for Soap Making
Students titrate a sample of fatty acids with standardized sodium hydroxide solution. From the amount of base needed for neutralization and the mass of sample used for titration, the apparent average molar mass of the sample is determined. Students use their results to determine whether or not their sample matched the fatty acid ratio best suited for soap making.
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Gas Law Investigation
This experiment requires two lab periods. In the first lab, students investigate the reaction of an Alka-Seltzer® tablet and water to determine the variables that affect the amount of gas produced from the reaction. Students also become familiar with the use of the gas collection apparatus. In the second lab, students pick from one of two scenarios. Each scenario involves a gas evolution experiment. Students use the gas collection apparatus from the first lab to collect data.
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Gasoline Additive
Students determine the freezing point depression constant, Kf, of t-butanol. They then calculate the amount of ethanol that should be added to 1 kg of t-butanol to keep it fluid at -10°F.
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Hydrogen Peroxide Analysis
Students determine the percent of hydrogen peroxide in store-bought hydrogen peroxide by titration with potassium permanganate. The potassium permanganate is standardized by students with titration of solid sodium oxalate.
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Programing the "Rinse Robot"
During the initial part of this exercise, students will attach a chemical group to a solid material inside a reaction tube. Not all of this chemical group will become attached to the solid material. This unattached chemical group is "free" and if not removed will cause unwanted reactions when other chemical groups are added to the reaction tube. This exercise uses thin layer chromatography to determine if any of the free chemical compound is present in the reaction tube. If the free chemical compound is present, TLC is used to determine the minimum number of rinse cycles necessary to completely remove the free chemical compound from the reaction tube.
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Quality Control at Kality Krunchers Dill Pickle Factory
This is a two week experiment. During the first lab period, students determine the conditions for a precise, reproducible titration of a brine solution with sodium hydroxide and the indicator, phenolphthalein. During the second week, students titrate pickle juice. They need to solve the problem of the interfering color of the pickles and decide if a more dilute solution of sodium hydroxide would be appropriate.
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Real-World Projects: Challenges From the Polymer Industry
This exploration involves two different scenarios that require the use of infrared spectroscopy: In "Wrapping It Up at the Submarine Sandwich Shop," students take an infrared spectrum of Reynold’s brand plastic wrap and of an unknown plastic wrap. In "Lumpy High-Density Polyethylene Bottles," students use infrared spectroscopy to determine if the lumps in a polyethylene bottle are polyethylene or a contaminant. Detailed information on operating an infrared spectrometer is provided for the students.
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Sorting Plastics for Recycling
Students use the difference in densities of polymers and flame tests as a basis for the development of a scheme to separate plastics.
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The Art of Soap Making
These open-ended problems involve students in multi-week explorations. Students have access to Emery’s Analytical Procedures1 and Technical Bulletin 140A, Processes and Facilities.2 The students will use at least one analytical testing procedure to solve the problems stated in the scenarios
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The Floating Egg Problem
Students work in groups of four to make a salt solution that will "float" an egg (according to their definition of "float"). Each student then determines the density of the group’s salt solution by using both a pipet and a graduated cylinder. They compare the results to determine the effect that the volume-measuring device has on calculating the density. Students also explore how the freshness of the raw egg affects their results.
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The Visible Spectrocopy Expert Witness Problem
This is a two-week lab in which students explore some of the basics of spectrophotometric analysis and then apply what they have learned to solve a forensic science problem. In week one, students investigate absorbance as a function of wavelength and as a function of concentration and use this information to identify the concentration of the solution. Students are then given a spectrophotometric method for determining salicylates in blood and are asked to determine the validity and reliability of this method. To do this, students must test a modified version of the procedure. The modification is mandated by the nature of the equation and solutions which are deliberately provided to the students. The modifications to be done are decided by the students, but include the size of the sample and how the sample is made.
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Using the Spectrometer to Analyze a Mixture
This experiment is designed to introduce students to the spectrophotometer and the decisions that must be made in using it as a means of gaining information about a system. Because students need to learn the skills, this experiment is very guided in design.