1. Rusting of iron: This is a classic example of a chemical change that does not involve living organisms. When iron is exposed to oxygen and water, it undergoes a chemical reaction to form iron oxide, or rust. The reaction can be represented as:
4Fe(s) + 3O2(g) + 6H2O(l) → 4Fe(OH)3·xH2O(s)
2. Burning of wood: When wood is burned, it undergoes a chemical change to form carbon dioxide and water vapor. The reaction can be represented as:
C6H12O6(s) + 6O2(g) → 6CO2(g) + 6H2O(g)
3. Mixing of acid and base: When an acid and a base are mixed, they undergo a chemical reaction to form a salt and water. The reaction can be represented as:
HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
