2.- Balancea las siguientes reacciones químicas como lo vimos en días anteriores en el tema de “reacciones químicas”. BaCl2 + Na2SO4 NaCl + BaSO4

Fe + HBr FeBr3 + H2

KClO3 KCl + O2

it is the most commonly accepted one

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.