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Flinn Lab Activities and Demonstrations
Chemical Equilibrium—Laboratory Kits, continued
Applications of Le Chatelier’s Principle— General Chemistry Guided-Inquiry Experiment See page 16.
The Equilibrium Constant—
Student Laboratory Kit
By: The Flinn Staff
The more a reaction at equilibrium changes, the more it stays the same! That’s because the only “constant” for a reaction at equilibrium is a mathematical relationship of concentrations called the equilibrium constant. In this quantitative experiment, students use colorimetry to determine the equilibrium constant for a reversible chemical reaction. Students first measure the absorbance of a reference solution contain- ing a known concentration of the product. They then prepare solutions having different starting concentrations of reactants, and allow the solutions to come to equilibrium. The equilibrium concentration of the product in each solution is determined by comparing its absorbance to that of the reference solution. The equilibrium constant for the reaction can then be calculated using stoichiometry and the balanced chemical equation. Includes all the chemicals and pipets needed for the experi- ment, along with reproducible student handouts, detailed background information, and complete Instructor’s Notes with sample data and answers to all questions.
Complete for 30 students working in pairs.
Chemical Equilibrium—Demonstration Kits
Common Ion Effect—
Chemical Demonstration Kit
By: The Flinn Staff
In this set of three demonstrations, students will observe a series of dramatic changes when common ions are added to solutions at equilib- rium. The results illustrate the nature of equilibrium and Le Chatelier’s principle.
• Adding strong and weak acid solutions to cylinders containing a white
powder causes the cylinders to overflow with colorful foam.
• Blowing bubbles into a blue solution changes the color of the solution to yellow. Stirring in a white powder causes the solution to revert back to blue. Blowing again into the solution returns the original yellow.
• Adding a clear liquid to a yellow solution produces an orange mixture. Stir in a white powder and the yellow reappears. Repeating the proce- dure sets up a color oscillation.
Demonstration Notes and enough chemicals to perform each demon-
stration seven times are included.
Concepts: Common ion effect, equilibrium, Le Chatelier’s principle. Time Required: 20 minutes
Chemicals Provided: Hydrochloric acid, acetic acid, sodium acetate, sodium chloride, sodium bicarbonate, sodium carbonate, ammonium hydroxide, ammonium chloride, phenolphthalein solution, bromthymol blue solution, alizarin yellow R solution.
1-800-452-1261
flinnsci.com
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The Equilibrium Constant—Student Laboratory Kit AP6619
Catalog No.
Description
Price/Each
AP6619
The Equilibrium Constant— Student Laboratory Kit
$44.05
Common Ion Effect—Chemical Demonstration Kit AP7043
Catalog No.
Description
Price/Each
AP7043
Common Ion Effect— Chemical Demonstration Kit
$57.40
CHEMICAL EQUILIBRIUM—DEMONSTRATION KITS continued on next page.