Balancing Chemical Equations Worksheet - Free Printable

Here is the fully balanced set of chemical equations with step-by-step explanations for each.

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1. Fe + H₂SO₄ → Fe₂(SO₄)₃ + H₂

This is a single displacement reaction where iron displaces hydrogen from sulfuric acid.

- Right side: Fe₂(SO₄)₃ has 2 Fe and 3 SO₄ groups.
- Left side: H₂SO₄ provides 1 SO₄ per molecule → need 3 H₂SO₄ to get 3 SO₄.
- That gives 6 H atoms on left → need 3 H₂ on right to balance H.
- Now Fe: 2 on right → need 2 Fe on left.

✔ Balanced equation:
2 Fe + 3 H₂SO₄ → 1 Fe₂(SO₄)₃ + 3 H₂

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2. CH₄ + O₂ → CO₂ + H₂O

Combustion of methane.

- C: 1 on both sides → OK.
- H: 4 on left → need 2 H₂O on right (→ 4 H).
- O: Right side = 2 (from CO₂) + 2 (from 2 H₂O) = 4 O → need 2 O₂ on left.

✔ Balanced equation:
1 CH₄ + 2 O₂ → 1 CO₂ + 2 H₂O

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3. SiCl₄(l) + H₂O(l) → SiO₂(s) + HCl(aq)

Hydrolysis of silicon tetrachloride.

- Si: 1 on both sides → OK.
- Cl: 4 on left → need 4 HCl on right.
- H: 4 H in 4 HCl → need 2 H₂O on left (→ 4 H).
- O: 2 H₂O gives 2 O → matches SiO₂.

✔ Balanced equation:
1 SiCl₄ + 2 H₂O → 1 SiO₂ + 4 HCl

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4. AgI + Na₂S → Ag₂S + NaI

Double displacement reaction.

- Ag: 2 on right → need 2 AgI on left.
- I: 2 I from 2 AgI → need 2 NaI on right.
- Na: 2 Na from Na₂S → matches 2 NaI.
- S: 1 on both sides → OK.

✔ Balanced equation:
2 AgI + 1 Na₂S → 1 Ag₂S + 2 NaI

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5. NH₃ + O₂ → NO + H₂O

Oxidation of ammonia.

Use algebraic method or trial:

- N: 1 on both sides → OK.
- H: 3 on left → need 3/2 H₂O → avoid fractions → multiply all by 2 later.
- Try: 4 NH₃ + 5 O₂ → 4 NO + 6 H₂O
- N: 4 = 4
- H: 12 = 12
- O: 10 = 4 (NO) + 6 (H₂O) = 10 → perfect!

✔ Balanced equation:
4 NH₃ + 5 O₂ → 4 NO + 6 H₂O

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6. FeO₃(s) + CO(g) → Fe(l) + CO₂(g)

*Note: FeO₃ is not a standard compound — likely meant to be Fe₂O₃ (iron(III) oxide). Assuming typo.*

Assume: Fe₂O₃ + CO → Fe + CO₂

- Fe: 2 on left → need 2 Fe on right.
- O: 3 on left → need 3 CO₂? But that would require 3 C → mismatch.
- Balance O: Each CO takes 1 O to become CO₂ → need 3 CO to remove 3 O from Fe₂O₃ → produces 3 CO₂.
- Fe: 2 → so 2 Fe.

✔ Balanced equation:
1 Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂

*(If you insist on FeO₃, it’s unstable and not standard — this is the correct industrial reaction.)*

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7. SiO₂ + HF → SiF₄ + H₂O

Reaction of silica with hydrofluoric acid.

- Si: 1 = 1 → OK.
- F: 4 on right → need 4 HF on left.
- H: 4 H from 4 HF → need 2 H₂O on right.
- O: 2 from SiO₂ → matches 2 H₂O.

✔ Balanced equation:
1 SiO₂ + 4 HF → 1 SiF₄ + 2 H₂O

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8. NaBr + Cl₂ → NaCl + Br₂

Halogen displacement (Cl₂ displaces Br⁻).

- Br: 2 on right → need 2 NaBr on left.
- Na: 2 → need 2 NaCl on right.
- Cl: 2 on left (Cl₂) → matches 2 NaCl.

✔ Balanced equation:
2 NaBr + 1 Cl₂ → 2 NaCl + 1 Br₂

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9. (NH₄)₃PO₄ + Pb(NO₃)₄ → Pb₃(PO₄)₄ + NH₄NO₃

Double displacement. Check charges:

- (NH₄)₃PO₄: NH₄⁺ and PO₄³⁻ → correct.
- Pb(NO₃)₄: Pb⁴⁺ and NO₃⁻ → correct.
- Product: Pb₃(PO₄)₄ → 3×Pb⁴⁺ = 12+, 4×PO₄³⁻ = 12- → correct.
- NH₄NO₃: 1:1 ratio.

Balance:

- PO₄: 4 on right → need 4 (NH₄)₃PO₄ on left → gives 12 NH₄⁺.
- Pb: 3 on right → need 3 Pb(NO₃)₄ on left → gives 12 NO₃⁻.
- Right: 12 NH₄NO₃ → 12 NH₄⁺ and 12 NO₃⁻ → perfect.

✔ Balanced equation:
4 (NH₄)₃PO₄ + 3 Pb(NO₃)₄ → 1 Pb₃(PO₄)₄ + 12 NH₄NO₃

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10. Mg(OH)₂ + HCl → MgCl₂ + H₂O

Acid-base neutralization.

- Mg: 1 = 1 → OK.
- Cl: 2 on right → need 2 HCl on left.
- H: 2 from Mg(OH)₂ + 2 from 2 HCl = 4 H → need 2 H₂O on right.
- O: 2 from Mg(OH)₂ → matches 2 H₂O.

✔ Balanced equation:
1 Mg(OH)₂ + 2 HCl → 1 MgCl₂ + 2 H₂O

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## ✔ Final Answer Summary:

1. 2 Fe + 3 H₂SO₄ → 1 Fe₂(SO₄)₃ + 3 H₂
2. 1 CH₄ + 2 O₂ → 1 CO₂ + 2 H₂O
3. 1 SiCl₄ + 2 H₂O → 1 SiO₂ + 4 HCl
4. 2 AgI + 1 Na₂S → 1 Ag₂S + 2 NaI
5. 4 NH₃ + 5 O₂ → 4 NO + 6 H₂O
6. 1 Fe₂O₃ + 3 CO → 2 Fe + 3 CO₂ *(assuming FeO₃ was a typo for Fe₂O₃)*
7. 1 SiO₂ + 4 HF → 1 SiF₄ + 2 H₂O
8. 2 NaBr + 1 Cl₂ → 2 NaCl + 1 Br₂
9. 4 (NH₄)₃PO₄ + 3 Pb(NO₃)₄ → 1 Pb₃(PO₄)₄ + 12 NH₄NO₃
10. 1 Mg(OH)₂ + 2 HCl → 1 MgCl₂ + 2 H₂O

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Let me know if you’d like to see the step-by-step balancing process for any specific equation!