Numerical Problems

Solution: Step 1: Count atoms on both sides

Left: Fe=1, H=2, O=1
Right: Fe=3, H=2, O=4

Step 2: Balance iron by putting 3 before Fe 3Fe + H₂O → Fe₃O₄ + H₂

Step 3: Balance oxygen by putting 4 before H₂O
3Fe + 4H₂O → Fe₃O₄ + H₂

Step 4: Balance hydrogen by putting 4 before H₂ 3Fe + 4H₂O → Fe₃O₄ + 4H₂

Final Answer: 3Fe + 4H₂O → Fe₃O₄ + 4H₂

Solution: This is a combination reaction because:

Two reactants (CaO and H₂O) combine
To form one product Ca(OH)₂
It follows the pattern A + B → AB

Solution: a) Zinc (Zn) is oxidized – it loses electrons to form Zn²⁺ ions b) Copper (Cu²⁺) is reduced – it gains electrons to form Cu metal This is a redox reaction where zinc displaces copper.