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Chemical Equilibrium
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Chemical Equilibrium—Demonstration Kits,
continued
Demonstrate Phase Changes of CO2—
Demonstration Kit
By: Walter Rohr, Retired
Eastchester High School, Eastchester, NY
An ingenious idea to introduce and demonstrate phase diagrams and triple point using dry ice. At atmospheric pressure carbon dioxide exists only as a solid or gas. However, in a closed system, liquid carbon dioxide will exist when the pressure exceeds 5 atmospheres. The triple point is when all three states of carbon dioxide (solid, liquid, and gas) are simultaneously present in a closed system. Using a unique device called a Triple Point of CO2 Apparatus, all three phases of CO2 can now be easily and safely observed. The apparatus comes with a large pressure gauge to monitor the pressure changes in the apparatus. This is a terrific lab activity. Concepts: Equilibrium, phase diagrams, triple point, sublimation. Time Required: 20 minutes
Materials Provided: Triple point of CO2 apparatus, detailed instruc- tions and teaching notes.
Note: Dry ice is required, but not provided.
Equilibrium in a Syringe— Chemical Demonstration Kit By: The Flinn Staff
It’s bubbly, it’s colorful—it’s equilibrium in a syringe! Use ordinary seltzer water, an acid–base indicator and a large syringe to transform a common gas solubility phenomenon into an exciting, hands-on demonstration. An acid–base solution is added to the seltzer water, and a portion of the solution is drawn into the syringe. Students note the pH by comparison to the indicator color chart. As the temperature and pressure of the solution in the syringe are varied, the solubility of carbon dioxide gas changes. Students observe the equilibrium shifts in the syringe as they monitor the pH of the solution.
Concepts: Equilibrium, gas solubility, acid–base indicators, Le Chatelier’s principle.
Time Required: 20 minutes
Materials Provided: 140-mL syringe, seltzer water, bromcresol green indicator solution, indicator color chart.
Note: The demonstration requires carbon dioxide. A supplemental procedure for generating carbon dioxide is included.
Demonstrate Phase Changes of CO2—Demonstration Kit AP4505
Catalog No.
Description
Price/Each
AP4505
Demonstrate Phase Changes of CO2— Demonstration Kit
$70.30
AP7484
Dry Ice Maker
585.10
Equilibrium in a Syringe—Chemical Demonstration Kit AP6644
CHEMICAL EQUILIBRIUM—DEMONSTRATION KITS continued on next page.
Catalog No.
Description
Price/Each
AP6644
Equilibrium in a Syringe—Chemical Demonstration Kit
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