When you mix vinegar and baking soda together why is it cold?

Baking soda and vinegar gets cold in a reaction called an endothermic reaction. Ectothermic reactions get warm, endo cold. All the heat is taken in by the baking soda and used as energy. If you add more baking soda, more baking soda will take in energy and make it colder.

Source(s): Fith Grade science project done in Los Gatos, CA