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.
Time Required: Minutes
- Pour the citric acid solution in a styrofoam coffee cup. Use a thermometer or other temperature probe to record the initial temperature.
- Stir in the baking soda (sodium bicarbonate). Track the change in temperature as a function of time.
- The reaction is: H3C6H5O7(aq) + 3 NaHCO3(s) → 3 CO2(g) + 3 H2O(l) + Na3C6H5O7(aq)
- When you have completed your demonstration or experiment, simply wash the cup out in a sink. No toxic chemicals to mess with!
- Feel free to vary the concentration of the citric acid solution or the quantity of sodium bicarbonate.
- 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.
What You Need
- 25 ml citric acid soln
- 15 g baking soda
- styrofoam cup
- stirring rod