Page 19 - Demo

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Guided-Inquiry Experiments for General Chemistry
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Guided-Inquiry Experiments for General Chemistry, continued
Buffers in Household Products—Laboratory Kit
By: The Flinn Staff
Many household products contain buffering chemicals such as citric acid, sodium carbonate, sodium benzoate, and phosphates or phosphoric acid. The lab begins with an introductory activity to identify the buffer- ing regions in the neutralization of a polyprotic weak acid. The results provide a model for guided-inquiry design of a procedure to determine the buffering agents in eight different household products, including foods and beverages and over-the-counter drugs. Procedures may include creating titration curves, calculating pKa values, and analyzing the buffer capacity and composition. Students may recommend addi- tional consumer products for further inquiry study.
Complete for 24 students working in pairs.
Designing a Hand Warmer—Laboratory Kit
By: The Flinn Staff
From instant cold packs to flameless ration heaters and hand warmers, the energy changes accompanying physical and chemical transfor- mations have many consumer applications. The backbone of these applications is calorimetry—measuring heat transfer.
In this guided-inquiry lab, students investigate the energy changes accompanying the formations of solutions for common laboratory salts, and then apply the results to design a hand warmer that is reliable, safe, nontoxic, and inexpensive. The students begin by familiarizing themselves with the principles of calorimetry and heat of solution calculations. The results provide a model for the guided-inquiry chal- lenge. Students are given a series of solids, along with their costs and individual Safety Data Sheets (SDS). The challenge is to determine the heat of solution for each solid and analyze the cost and safety informa- tion to propose a design for the best, all-around hand warmer. Students love a challenge—this design challenge will surely inspire creativity!
Complete for 24 students working in pairs.
Gravimetric Analysis of Calcium and Hard Water— Laboratory Kit
By: The Flinn Staff
The purpose of this advanced inquiry lab is to investigate the suitability of gravimetric analysis for determining the amount of water hardness in the form of calcium carbonate in various water samples. Six samples, representing a wide range of potential water hardness from 50 ppm to 500 ppm, will be analyzed as part of a cooperative class investigation to determine the accuracy and sensitivity of gravimetric analysis for water hardness testing.
The lab begins with an introductory activity to develop skill in the calculations and techniques of gravimetric analysis, in particular, quantitative transfer and vacuum or gravity filtration. The procedure provides a model for guided-inquiry design of the cooperative class investigation described above. Antacid tablets are also provided as an opportunity for further inquiry—the use of gravimetric analysis to determine the amount of calcium in an over-the-counter medication.
Complete for 24 students working in pairs.
Buffers in Household Products—Laboratory Kit AP7982
Catalog No.
Description
Price/Each
AP7982
Buffers in Household Products—Laboratory Kit
$54.45
Catalog No.
Description
Price/Each
AP7972
Designing a Hand Warmer—Laboratory Kit
$55.65
GUIDED-INQUIRY EXPERIMENTS FOR GENERAL CHEMISTRY continued on next page.
Designing a Hand Warmer—Laboratory Kit AP7972
Catalog No.
Description
Price/Each
AP7973
Gravimetric Analysis of Calcium and Hard Water—Laboratory Kit
$31.75
Gravimetric Analysis of Calcium and Hard Water—Laboratory Kit AP7973