Caution: Use appropriate safety guidelines in performing demonstrations.
This demonstration illustrates that most active metals replace hydrogen from an acid.
6 M Hydrochloric acid, HCl
Small samples of any four metals (Cu, Mg, Al, Zn, Fe, or Sn)
Slant-top overhead apparatus or petri dishes (or 50-mL beakers or titer plates)
6 M HCl is corrosive and must be handled with care. Goggles should be worn.
Place vessels on an overhead projector. Add 6 M HCl to each vessel, followed by the sequential addition of the metal samples. Observe; ask students to explain the results.
Demonstration 2: Nature of Indicators
Many common foods have natural indicators.
Natural Indicators: Red cabbage juice, grape juice, or fillings from berry fruit Pies
Baking soda (sodium bicarbonate), NaHCO3
6 Petri dishes, slant test tube apparatus, or 50-mL beakers.
Most of the materials are very weak acids or bases, but goggles should still be worn.
Place natural indicators in each of three dishes, test tubes, or beakers. You might want to dilute the fruit fillings with a little distilled water and use the resulting mixture as the sample. Add vinegar to one solution, add baking soda to another, and use the third as a control. Have students make observations and state their conclusions.
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