1. CaO + H2O → Ca(OH)2
- CaO + H2O → Ca(OH)2 (unbalanced)
- Ca + O + 2H → Ca + 2O + 2H (counting atoms)
- Ca + O + 2H → Ca + 2O + 2H (same number of atoms on both sides)
- The equation is already balanced.
2. a) Mg + O2 → MgO
- Mg + O2 → MgO (unbalanced)
- Mg + O + O → Mg + O (counting atoms)
- Mg + O2 → 2MgO (same number of atoms on both sides)
- The balanced equation is Mg + O2 → 2MgO.
b) Fe + O2 → Fe2O3
- Fe + O2 → Fe2O3 (unbalanced)
- Fe + O + O + O → Fe + Fe + O + O + O (counting atoms)
- 4Fe + 3O2 → 2Fe2O3 (same number of atoms on both sides)
- The balanced equation is 4Fe + 3O2 → 2Fe2O3.
c) Cu + O2 → CuO
- Cu + O2 → CuO (unbalanced)
- Cu + O + O → Cu + O (counting atoms)
- 4Cu + 1O2 → 4CuO (same number of atoms on both sides)
- The balanced equation is 4Cu + O2 → 4CuO.
3. a) Na+Cl2→NaCl
- Na+Cl2→NaCl (unbalanced)
- Na+Cl+Cl→Na+Cl (counting atoms)
- 2Na+Cl2→2NaCl (same number of atoms on both sides)
- The balanced equation is 2Na+Cl2→2NaCl.
b) N2+H2→NH3
- N2+H2→NH3 (unbalanced)
- N+N+H+H→N+H+H (counting atoms)
- N2+3H2→NH3 (same number of atoms on both sides)
- The balanced equation is N2+3H2→NH3.
c) Pb(OH)2 + HCl → PbCl2 + H2O
- Pb(OH)2 + HCl → PbCl2 + H2O (unbalanced)
- Pb+O+H+H+Cl→Pb+Cl+Cl+H+O (counting atoms)
- Pb(OH)₂+ 4HCl → PbCl₂+ ₂H₂O (same number of atoms on both sides)
- The balanced equation is Pb(OH)₂+ 4HCl → PbCl₂+ ₂H₂O.
d) P4 +O2 →P2O3
- P4 +O₂ →P₂O₃ (unbalanced)
- P+P+P+P+O+O→P+P+O+O+O (counting atoms)
- P₄+5O₂→P₂O₃ (same number of atoms on both sides)
- The balanced equation is P₄+5O₂→P₂O₃.
I hope this helps! Let me know if you have any other questions.