Sidebar: Recipes for Endothermic and Exothermic Reactions

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This week we learned about endothermic and exothermic reactions in Lesson 4. Now let’s take a look at examples of these reactions.

Reaction 1.

Materials:

  • 4 3.68 g packets Crystal Light Natural Pink Lemonade (primary ingredient citric acid)
  • Baking soda
  • Water
  • Large Styrofoam cup
  • Thermometer
  • Spoon or stirring rod

Procedure 1:

  1. In a sink, tub, or outdoors in an area that can get messy, mix the 4 packets of Crystal Light into approx. 100 mL of water in the Styrofoam cup.
  2. Take the temperature of the solution, taking care not to rest the thermometer on the bottom or side of the cup.
  3. Add about 1/3 cup baking soda.
  4. As the reaction starts to slow, take the temperature again.
  5. Adjust the amounts of ingredients if the temperature change was not apparent.

Did the temperature go up or down?

 

experiment-cup-citric

Reaction 2:

Materials:

  • 2 Tablespoons active yeast
  • Water
  • Large Styrofoam cup
  • Thermometer
  • Hydrogen peroxide (from drug store)
  • Spoon or stirring rod

Procedure 2.

  1. In a sink, tub, or or outdoors in an area that can get messy, mix the yeast  into approx. 100 mL of water in the Styrofoam cup. (You may also add a squirt of dish detergent)
  2. Take the temperature of the solution, taking care not to rest the thermometer on the bottom or side of the cup.
  3. Add about 1/3 cup hydrogen peroxide.
  4. As the reaction starts to slow, take the temperature again.
  5. Adjust the amounts of ingredients if the temperature change was not apparent.

Did the temperature go down or up?

If you chose to, leave a comment to let us know how the experiment turned out.

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