Classifying Chemical Reactions Worksheet featuring 15 unbalanced chemical equations for students to identify reaction types.

Let's classify each chemical reaction from the worksheet based on its type. We'll go through each one, identify the reaction type(s), and explain why.

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1. PbCl₂ + AgNO₃ → Pb(NO₃)₂ + AgCl

- Classification: Double replacement
- Explanation: Two compounds exchange ions: Pb²⁺ pairs with NO₃⁻, and Ag⁺ pairs with Cl⁻.
- Also a precipitation reaction (AgCl is insoluble), but not explicitly listed in options.
- Not redox (no change in oxidation states).
- Answer: Double replacement

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2. NH₃ + HCl → NH₄Cl

- Classification: Acid/base
- Explanation: Ammonia (NH₃) acts as a base, HCl is an acid; they form ammonium chloride (a salt). This is a classic acid-base neutralization.
- It’s also a synthesis reaction (two substances combine to form one product).
- Answer: Acid/base, synthesis

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3. AlCl₃ + Na₂SO₄ → Al₂(SO₄)₃ + NaCl

- Classification: Double replacement
- Explanation: Ions are exchanged between two ionic compounds: Al³⁺ pairs with SO₄²⁻, and Na⁺ pairs with Cl⁻.
- Answer: Double replacement

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4. Zn + S → ZnS

- Classification: Synthesis
- Explanation: Two elements combine to form a compound.
- Also redox: Zn is oxidized (0 → +2), S is reduced (0 → -2).
- Answer: Synthesis, redox

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5. Al₂(SO₄)₃ + BaCl₂ → BaSO₄ + AlCl₃

- Classification: Double replacement
- Explanation: Exchange of ions: Ba²⁺ swaps with Al³⁺.
- BaSO₄ is insoluble — precipitation occurs.
- Answer: Double replacement

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6. Al₂S₃ → Al + S

- Classification: Decomposition
- Explanation: A single compound breaks down into its constituent elements.
- Also redox: Al goes from +3 to 0 (reduction), S from -2 to 0 (oxidation).
- Answer: Decomposition, redox

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7. H₂SO₄ + Fe → H₂ + FeSO₄

- Classification: Single replacement
- Explanation: Iron (Fe) replaces hydrogen in sulfuric acid.
- Also redox: Fe oxidized (0 → +2), H⁺ reduced (+1 → 0).
- Answer: Single replacement, redox

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8. C₁₂H₂₂O₁₁ + O₂ → CO₂ + H₂O

- Classification: Combustion
- Explanation: A hydrocarbon (or carbohydrate) reacts with oxygen to produce CO₂ and H₂O.
- Also redox: Carbon oxidized, oxygen reduced.
- Answer: Combustion, redox

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9. Mg(OH)₂ + H₂SO₄ → MgSO₄ + H₂O

- Classification: Acid/base
- Explanation: Base (Mg(OH)₂) reacts with acid (H₂SO₄) to form salt (MgSO₄) and water.
- Also double replacement (ions swap).
- Answer: Acid/base, double replacement

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10. NaOH + CuSO₄ → Na₂SO₄ + Cu(OH)₂

- Classification: Double replacement
- Explanation: Ions exchange: Na⁺ with Cu²⁺.
- Cu(OH)₂ is a precipitate (insoluble).
- Answer: Double replacement

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11. C₄H₁₂ + O₂ → H₂O + CO₂

- Classification: Combustion
- Explanation: Hydrocarbon burns in oxygen to produce CO₂ and H₂O.
- Note: C₄H₁₂ is likely a typo; probably meant C₄H₁₀ (butane). But regardless, it’s combustion.
- Also redox.
- Answer: Combustion, redox

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12. Fe + O₂ → Fe₂O₃

- Classification: Synthesis
- Explanation: Iron combines with oxygen to form iron(III) oxide.
- Also redox: Fe oxidized (0 → +3), O reduced (0 → -2).
- Answer: Synthesis, redox

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13. Mg₃(PO₄)₂ + H₂ → Mg + H₃PO₄

- Classification: Single replacement
- Explanation: Hydrogen replaces magnesium in the compound.
- Also redox: H₂ oxidized (0 → +1), Mg reduced (+2 → 0).
- Answer: Single replacement, redox

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14. NH₄NO₃ → N₂O + H₂O

- Classification: Decomposition
- Explanation: One compound breaks down into two products.
- Also redox: Nitrogen in NH₄⁺ is oxidized, nitrogen in NO₃⁻ is reduced (disproportionation).
- Answer: Decomposition, redox

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15. Cl₂ + KBr → KCl + Br₂

- Classification: Single replacement
- Explanation: Chlorine displaces bromine from potassium bromide.
- Also redox: Cl₂ reduced (0 → -1), Br⁻ oxidized (-1 → 0).
- Answer: Single replacement, redox

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✔ Final Answers:

1. Double replacement
2. Acid/base, synthesis
3. Double replacement
4. Synthesis, redox
5. Double replacement
6. Decomposition, redox
7. Single replacement, redox
8. Combustion, redox
9. Acid/base, double replacement
10. Double replacement
11. Combustion, redox
12. Synthesis, redox
13. Single replacement, redox
14. Decomposition, redox
15. Single replacement, redox

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