Question

Which of the following is an example of an exothermic reaction? silt settling out of muddy water, bubbles forming in soda, photosynthesis or fireworks

Answer 1

Fireworks
An exothermic reaction is one where the products have lower energy than the reactants, so the reaction yields energy. The chemical compounds present in firework fuel release a lot of energy upon oxidation. Photosynthesis is endothermic, settling of silt is not a chemical reaction, it is a physical change. Finally, the bubble formation in soda is not exothermic; otherwise, the sodas would become very hot very fast.