Definition of Chemical Reactions
Chemical reactions occur when atoms or molecules interact to form new substances by breaking and forming chemical bonds. Reactants, the starting materials, transform into products, the resulting substances, through a reorganization of atoms. This process follows the law of conservation of mass, ensuring no atoms are created or destroyed, only rearranged.
Key Principles and Components
The core principles involve energy changes and bond dynamics. Bonds between atoms in reactants break, requiring energy (endothermic), while new bonds form in products, releasing energy (exothermic). Reactions can be represented by balanced equations, such as 2H₂ + O₂ → 2H₂O, highlighting stoichiometry. Factors like temperature, concentration, and catalysts influence reaction rates.
Practical Example: Rusting of Iron
A common example is the rusting of iron, where iron (Fe) reacts with oxygen (O₂) and water (H₂O) to form iron oxide (Fe₂O₃·nH₂O). The equation is 4Fe + 3O₂ + 2nH₂O → 2Fe₂O₃·nH₂O. This slow oxidation process illustrates how environmental factors accelerate bond breaking and reforming, leading to corrosion.
Importance and Real-World Applications
Chemical reactions underpin biological processes like respiration, industrial manufacturing such as fertilizer production via the Haber-Bosch process, and everyday phenomena like cooking or combustion in engines. Understanding them enables advancements in medicine, energy, and materials science, while addressing misconceptions about reactions always being visible or explosive.