A chemical reaction is a process where original materials transform into new ones. In the context of chemical reactions, the substances that begin the process are considered “inputs,” while the newly formed substances are the “outputs.” This distinction helps in understanding the flow of matter during chemical transformations.
Reactants Are Inputs
Reactants are the initial substances that are present at the start of any chemical reaction. They serve as the raw materials that are chemically altered to produce different substances. Reactants are the “inputs” consumed as the reaction proceeds, much like ingredients for baking a cake. Their chemical bonds are broken, and their atoms rearrange to form new molecular structures.
For example, when hydrogen gas reacts with oxygen gas, both hydrogen and oxygen are the reactants. They are the substances that are introduced into the reaction system. The amount of reactants dictates the potential yield of the new substances, making their role as inputs important to the entire process. They are the active participants that undergo change.
Products Are Outputs
Products are the new substances that are generated as a result of a chemical reaction. These materials are chemically distinct from the reactants and possess different properties. Continuing the baking analogy, the baked cake would be the output. It is a new entity formed from the transformation of the original ingredients. Products are considered “outputs” because they emerge from the chemical process.
In the reaction between hydrogen and oxygen, water is the product formed. Water has different chemical and physical properties compared to the hydrogen and oxygen gases from which it was formed. The properties of the products are a direct consequence of the specific arrangement of atoms that occurs during the reaction.
How Chemical Equations Show This
Chemical equations provide a concise visual representation of a chemical reaction, illustrating the input-output relationship. Reactants are always written on the left side of the equation. An arrow, often read as “yields” or “produces,” separates the reactants from the products. Products are always written on the right side of this arrow. This structural arrangement directly signifies the flow from inputs to outputs.
For instance, the equation 2H₂ + O₂ → 2H₂O shows hydrogen (H₂) and oxygen (O₂) as the reactants on the left, acting as inputs. The arrow points towards water (H₂O) on the right, indicating it as the product or output of the reaction. This visual layout reinforces that the initial substances are transformed into new ones. The atoms themselves are not created or destroyed during this process; rather, they are merely rearranged from their initial reactant configurations into new product configurations, reflecting the law of conservation of mass.