Guided Practice
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This lesson provides step-by-step practice identifying reaction types and balancing equations.
Balancing Strategy
- Write the unbalanced equation
- Count atoms of each element on both sides
- Balance one element at a time (save H and O for last)
- Use coefficients, never change subscripts
- Verify all atoms are balanced
Practice Problems
Problem 1: Balance: H2 + O2 → H2O
Answer: 2H2 + O2 → 2H2O
Problem 2: Identify the reaction type: 2Na + Cl2 → 2NaCl
Answer: Synthesis (combination) reaction
Problem 3: Balance: Fe + O2 → Fe2O3
Answer: 4Fe + 3O2 → 2Fe2O3
Problem 4: Identify: CaCO3 → CaO + CO2
Answer: Decomposition reaction
Problem 5: Balance: C3H8 + O2 → CO2 + H2O
Answer: C3H8 + 5O2 → 3CO2 + 4H2O
Problem 6: Identify: Zn + CuSO4 → ZnSO4 + Cu
Answer: Single replacement reaction
Problem 7: Balance: Al + HCl → AlCl3 + H2
Answer: 2Al + 6HCl → 2AlCl3 + 3H2
Problem 8: Identify: NaCl + AgNO3 → NaNO3 + AgCl
Answer: Double replacement reaction
Problem 9: Balance: CH4 + O2 → CO2 + H2O
Answer: CH4 + 2O2 → CO2 + 2H2O
Problem 10: Identify: 2H2O → 2H2 + O2
Answer: Decomposition reaction (electrolysis of water)