Why do chemical properties change? What do the prefixes exo- and endo- mean?
What happens to heat in an exothermic reaction?
What happens to heat in an endothermic reaction?

Chemical properties change because they go under a chemical reaction. The prefix exo- means outer and endo- is a convincing form meaning within. In an exothermic reaction the heat is released into the surroundings. In an endothermic reaction the temperature rises and the endothermic process absorbs heat and cools the surrounding

Answer ozone (o3) is made of three atoms of oxygen, it is a molecule;