Create an Endothermic Reaction

Try this easy chemistry experiment using just a few safe household products.

You can make a homemade cold pack using safe kitchen ingredients and a simple endothermic chemical reaction.
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Most endothermic reactions contain toxic chemicals, but this reaction is safe and easy. Indeed, this experiment requires no toxic chemicals -- a rarity in chemistry studies. Use it as a demonstration or vary the amounts of citric acid and sodium bicarbonate to make an experiment.

Materials

Citric acid and baking soda are available at most grocery stores. Citric acid is used for canning, while baking soda is used for baking.

Here's what you'll need:

  • 25 milliliters of citric acid solution
  • 15 grams of baking soda
  • plastic foam cup
  • thermometer
  • stirring rod

Creating the Reaction

  1. Pour the citric acid solution into a coffee cup. Use a thermometer or other temperature probe to record the initial temperature.
  2. Stir in the baking soda -- sodium bicarbonate. Track the change in temperature as a function of time.
  3. The reaction is: H3C6H5O7(aq) + 3 NaHCO3(s) → 3 CO2(g) + 3 H2O(l) + Na3C6H5O7(aq)
  4. When you have completed your demonstration or experiment, wash the cup out in a sink.

Tips for Success

  1. Feel free to vary the concentration of the citric acid solution or the quantity of sodium bicarbonate.
  2. An endothermic is a reaction that requires energy to proceed. The intake of energy may be observed as a decrease in temperature as the reaction proceeds. Once the reaction is complete, the temperature of the mixture will return to ​​room temperature.