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Product 12562

By: Walter Rohr, Retired , Eastchester High School, Eastchester, NY

The Hot and Cold Equilibrium Le Chatelier’s Principle Chemical Demonstration Kit is amazingly simple, but intriguing. Challenge students to explain the phenomenon observed when the tubes of violet solution are reversed in hot and cold water baths.

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Product Details

Challenge students to explain the phenomenon observed in this amazingly simple but intriguing demonstration. Pour some violet-colored solution into three different test tubes. Place one tube in cold water—the solution turns pink, from the bottom up. Place another tube in hot water—the solution turns a deep blue from the top down. Leave the third tube at room temperature—the solution remains violet. Watch what happens when the tubes are reversed in the hot and cold water baths. Teacher Demonstration Notes included.  

Concepts: 
Equilibrium, Le Chatelier’s Principle, density, absorption/transmission. 
Time Required: 
20 minutes 
Materials Provided: 
Cobalt chloride/alcohol solution, test tubes, and stoppers.

Correlation to Next Generation Science Standards (NGSS)

Science & Engineering Practices

Analyzing and interpreting data
Developing and using models
Constructing explanations and designing solutions

Disciplinary Core Ideas

MS-PS1.A: Structure and Properties of Matter
MS-PS1.B: Chemical Reactions
MS-PS4.A: Wave Properties
MS-PS4.B: Electromagnetic Radiation
HS-PS1.B: Chemical Reactions

Crosscutting Concepts

Patterns
Structure and function
Stability and change

Performance Expectations

MS-PS1-2. Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
MS-PS4-2. Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.
HS-PS1-2. Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
HS-PS1-6. Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium.