Final answer:
During a chemical reaction, the breaking of bonds in reactants and the forming of new bonds in products create different substances with new properties.
Step-by-step explanation:
During a chemical reaction, bonds between atoms are broken and new bonds are formed, leading to the creation of new substances. These substances, known as products, have different properties and chemical compositions than the starting materials, called reactants. For instance, the reaction 2H₂O → 2H₂ + O₂ describes the electrolysis of water, where the bonds of water molecules are broken to generate hydrogen and oxygen gases.
Energy plays a vital role in the making and breaking of chemical bonds. Energy is absorbed to break bonds and released when new bonds form, which can be observed in endothermic and exothermic reactions, respectively.
Furthermore, the rearrangement of atoms into new molecules sometimes produces new substances with the same elemental composition but a different structure, such as isomers.