Most people think that the smoke, bubbles, color, etc, are the actual CHANGE in a chemical reaction, but this isn’t true. The actual chemical change is unseen usually, the smoke, bubbles, etc, are just signs of the chemical change. In a chemical reaction/change, the substance of the element might change. Chemical reactions can be either spontaneous, requiring no input of energy or doesn’t need much help to start, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity. For instance,  if a solid (ice) was to be heated, it would melt and become a liquid. Then, if you were to heat the water (liquid), it would become a gas. This could reverse though. The gas would condense into a cloud, and it would eventually become a liquid because it would rain. Then, the run-off water could be frozen, and become a solid. The substances, or elements, in a chemical reaction are called the reactants. When the chemical change occurs, the reactants either A) remain intact, B) the are destroyed in the process of the chemical reaction taking place, or C) the chemical bonds are broken and rearranged to create a new substance/element.