Final answer:
A balanced chemical equation has the same number of each type of atom on both sides of the reaction. Upon checking each equation, (a) is not balanced, but (b) and (c) are correctly balanced.
Step-by-step explanation:
When determining if a chemical equation is balanced, one must ensure that the same number of each type of atom is present on both sides of the reaction.
Examples:
- Equation a: 2Na(s) + O₂(g) → 2Na₂O(s) is not balanced because it has 4 Sodium (Na) atoms on the product side but only 2 Sodium atoms on the reactant side.
- Equation b: CH4(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) is balanced with 1 Carbon (C) atom, 4 Hydrogen (H) atoms, and 4 Oxygen (O) atoms on both sides.
- Equation c: AgNO₃(aq) + 2KCl(aq) → AgCl(s) + KNO₃(aq) is balanced with 1 Silver (Ag), 1 Nitrogen (N), 3 Oxygen (O), 2 Potassium (K), and 2 Chlorine (Cl) atoms on each side.