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Flinn Lab Activities and Demonstrations
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Solutions and Solubility—Laboratory Kits,
continued
Solubility and Temperature—
Student Laboratory Kit
By: The Flinn Staff
The perfect lab activity for students to learn about solubility, solubility curves, saturated solutions and saturation temperature. The solubility of compounds in water can vary widely with temperature. In many cases, “rules” do not apply to solubility patterns, so the solubility of a chemical can only be determined through experimentation and construction of a solubility curve. In this lab activity, students will create the solubility curve for potassium nitrate—a compound with a solubility in water that increases 1700% from 0 to 100 °C! Students will measure saturation temperatures for six different concentrations of potassium nitrate, and then make a solu- bility curve from the data. Graphical analysis of the data allows students to determine at a glance whether a solution is unsaturated, saturated, or supersaturated. Includes reproducible student handouts, detailed back- ground information, Notes with sample data and answers to questions, and all necessary chemicals and consumable supplies.
Complete for 30 students working in pairs.
Analysis of Aluminum Potassium Sulfate— Classic General Chemistry Experiment
See page 21.
Solubility Matters—Measuring
the Ksp of Calcium Iodate—
Student Laboratory Kit
By: Bob Lewis, Retired, Downers Grove North H.S., Downers Grove, IL
John Little, Retired, St. Mary’s H.S., Stockton, CA
Students use an unusual titration technique to determine the equilibrium constant for the solubility of calcium iodate in water. Sodium thiosulfate solution is added dropwise from a pre-weighed bottle to a saturated solution of calcium iodate that has been mixed with excess potassium iodide. The iodate/iodide reaction generates elemental iodine, which undergoes reduc- tion when sodium thiosulfate is added. Starch is used as an indicator—the tell-tale blue color of the starch/iodine complex disappears instantly at the endpoint of the titration. Students calculate the concentration of iodate ion, the concentration of calcium ion and, finally, the solubility product constant—Ksp value—for calcium iodate. Equilibrium constant calculations do not have to be abstract, mind-numbing, number-crunching exercises. Let your students see where the numbers come from and what the numbers mean! Includes reproducible student handouts, detailed background information, complete Notes with sample data and answers to all ques- tions and all necessary chemicals and consumable supplies.
Complete for 30 students working in pairs. Fifteen reusable serologi- cal pipets and pipet bulbs are recommended and available separately.
Solubility and Temperature—Student Laboratory Kit AP6636
Catalog No.
Description
Price/Each
AP6636
Solubility and Temperature—Student Laboratory Kit
$24.05
Catalog No.
Description
Price/Each
AP6123
Solubility Matters—Measuring the Ksp of Calcium Iodate—Student Laboratory Kit
$50.55
GP7058
Serological Pipet, 5-mL Capacity
0.68
AP8607
Pipet Bulb, Rubber
3.85
SOLUTIONS AND SOLUBILITY—LABORATORY KITS continued on next page.
Solubility Matters—Measuring the Ksp of Calcium Iodate— Student Laboratory Kit
AP6123