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Flinn Lab Activities and Demonstrations
1-800-452-1261
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Acids, Bases and Indicators— Demonstration Kits, continued
Battle of the Acids—
Strong vs. Weak Acids—
Chemical Demonstration Kit
By: The Flinn Staff
Not all acids are created equal! Compare the “frothing and foaming” reaction of two different acids with calcium carbonate using our exclusive “rainbow acid” universal indicator. The indicator produces a rainbow spectrum of color changes in the pH range from 1 to 7. Students build connections linking the rate of reaction to the hydrogen ion concentration and pH scale as they “discover” the properties of strong and weak acids. Repeat the acid battle in the presence of their salts—how does this affect their properties? Students will see what it means to say that a reaction is irreversible or reversible. All of the observations put together will help students build a complete picture of strong versus weak acids. Concepts: Strong acid, weak acid, conjugate base, pH.
Time Required: 15 minutes
Chemicals Provided: Hydrochloric acid, acetic acid, calcium carbonate, sodium chloride, sodium acetate, “rainbow-acid” universal indicator. Note: A large demonstration tray is recommended. See AP5429 for a description of our fiberglass demonstration tray.
See free video at flinnsci.com.
Buffer Balancing Acts—
Chemical Demonstration Kit
By: The Flinn Staff
Buffers provide an essential acid–base balancing act in living cells, lakes and in many consumer products. What are buffers made of and how do they work? First, prepare an ideal pH 7 phosphate buffer—the same buffer that protects enzymes and proteins in cells. Next, use indicators to show how the buffer resists pH changes and protects against acids and bases. Students will learn not only what components are always present in a buffer, but also understand how each component plays a unique role in making the buffer work. Finally, apply what students have learned about buffers by testing the buffer capacity of Alka-Seltzer® tablets. Buffers are one of the most difficult concepts in acid–base chemistry. Concepts: pH, buffers, weak acid, conjugate base.
Time Required: 15 minutes
Chemicals Provided: Hydrochloric acid, sodium hydroxide solution, sodium phosphate (monobasic) and sodium phosphate (dibasic) solutions, bromthymol blue and universal indicators and Alka-Seltzer tablets.
See free video at flinnsci.com.
Disappearing Ink—
Chemical Demonstration Kit
By: David A. Katz, Retired, Wilmington, DE
It’s magic! It’s mystery! No—it’s science. Write secret messages with disappearing ink and then use chemistry to develop and transmit the messages. Students learn about the properties of a characteristic acid– base indicator and extend their understanding of pH and acid–base concepts. This demonstration is sure to engage your students’ interest. Students are eager to display their growing chemical knowledge when they develop the secret messages and explain the chemical basis of the disappearing ink phenomenon to curious visitors.
Concepts: Acids and bases, pH, indicators.
Time Required: 20–30 minutes
Chemicals Provided: Thymolphthalein indicator solution and sodium hydroxide solution.
See free video at flinnsci.com.
Battle of the Acids—Strong vs. Weak Acids— Chemical Demonstration Kit
AP6287
Catalog No.
Description
Price/Each
AP6287
Battle of the Acids—Strong vs. Weak Acids— Chemical Demonstration Kit
$50.10
AP5429
Demonstration Tray, Large
89.50
Buffer Balancing Acts—Chemical Demonstration Kit AP6288
Catalog No.
Description
Price/Each
AP6288
Buffer Balancing Acts—Chemical Demonstration Kit
$41.85
Disappearing Ink—Chemical Demonstration Kit AP8894
Catalog No.
Description
Price/Each
AP8894
Disappearing Ink—Chemical Demonstration Kit
$24.30
ACIDS, BASES AND INDICATORS—DEMONSTRATION KITS continued on next page.