A study of materials on the endothermic reaction in lower secondary school science : The experimental condition using sodium hydrogen carbonate and citric acid

The endothermic reaction is studied in lower secondary school science. In the text book, however, the reagents that require caution such as ammonium chloride and barium hydroxide were used for this experiment. Thus, in the present study, to obtain the suitable conditions for the endothermic reaction using sodium hydrogen carbonate and citric acid instead of ammonium chloride and barium hydroxide, we examined the effects of amount and ratio of the reagents on the reaction.