A chemical reaction is a fundamental process where one set of chemical substances transforms into another. This involves the rearrangement of atoms, resulting in new substances with different properties than the original materials. This transformation is distinct from physical changes, where a substance’s appearance might alter, but its underlying molecular structure remains unchanged.
Understanding Reactants
Reactants are the initial substances involved in a chemical reaction. One can think of reactants as the “ingredients” that are consumed or altered to form something new. For example, in photosynthesis, carbon dioxide and water serve as the reactants that plants utilize. These substances are placed on the left side of a chemical equation.
Understanding Products
Products are the new substances generated as a result of a chemical reaction. They possess different chemical properties compared to the reactants from which they were formed. In a chemical equation, products are written on the right side of the reaction arrow.
The Chemical Transformation Process
The transformation from reactants to products involves a process where chemical bonds are broken and new ones are formed. Atoms present in the reactants are rearranged to create different substances as products. This rearrangement does not involve the creation or destruction of atoms; instead, atoms simply change their partners. This adheres to the law of conservation of mass, which states that the total mass of the reactants before a reaction must equal the total mass of the products formed.
Representing Chemical Reactions
Chemical reactions are represented using chemical equations. These equations display the chemical formulas of the reactants on the left side and the products on the right side. An arrow (→) separates the reactants from the products and indicates the direction of the reaction. Plus signs (+) are used to separate multiple reactants or multiple products. Each substance’s physical state, such as solid (s), liquid (l), gas (g), or aqueous solution (aq), can be indicated in parentheses next to its formula.
Coefficients, which are numbers placed in front of chemical formulas, are used to balance equations. Balancing ensures that the number of atoms for each element is the same on both sides of the equation, reflecting the law of conservation of mass. For instance, a coefficient of ‘2’ in front of H₂O means there are two water molecules involved in the reaction.
Common Chemical Reactions in Daily Life
Chemical reactions are constantly occurring around us and within our bodies. One common example is the burning of wood, a combustion reaction. Here, wood reacts with oxygen from the air to produce carbon dioxide, water vapor, and ash. Another everyday reaction is the rusting of iron, where iron reacts with oxygen and water to form rust. The reaction between baking soda (sodium bicarbonate) and vinegar (acetic acid) is also a familiar chemical change, producing carbon dioxide gas, water, and a salt.