Final answer:
A chemical reaction is a process in which substances interact, leading to the change in ionic or covalent bonds to form new substances. Chemical bonds break and atoms rearrange during this process, and the law of conservation of mass applies to these reactions.
Step-by-step explanation:
A process in which substances interact in a way that changes ionic or covalent bonds is called a chemical reaction. In a chemical reaction, the chemical bonds of the starting substances, or reactants, break apart and atoms rearrange to form new substances with new bonds, known as products. A clear indication of a chemical reaction is the formation of new substances with different compositions and properties.
Chemical changes are always involved in a chemical reaction because the chemical composition of the substances is changed during the process. Reactants undergo a transformation, and new compounds or elements are produced as a result.
Chemical reactions are also governed by the law of conservation of mass, which states that in a closed system, matter is neither created nor destroyed. Therefore, chemical equations representing reactions must be balanced, demonstrating that mass is conserved by having an equal number of each type of atom on both sides of the equation.