How To Create an Endothermic Chemical Reaction (Safe)

Cold Chemical Reaction Example

You can make a homemade cold pack using safe kitchen ingredients and a simple endothermic chemical reaction.
You can make a homemade cold pack using safe kitchen ingredients and a simple endothermic chemical reaction. nolimitpictures / Getty Images

Most endothermic reactions contain toxic chemicals, but this reaction is safe and easy. Use it as a demonstration or vary the amounts of citric acid and sodium bicarbonate to make an experiment.

Difficulty: Average

Time Required: Minutes

Exothermic Reaction Materials

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

  • 25 ml citric acid solution
  • 15 g baking soda
  • styrofoam cup
  • thermometer
  • stirring rod

How To Do an Exothermic 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, simply wash the cup out in a sink. No toxic chemicals to mess with!

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.