Free Printable Balancing and Classifying Chemical Equations Worksheets - Free Printable

Let’s go through each reaction one by one. For each, we’ll:

1. Balance the chemical equation (make sure atoms on left = atoms on right).
2. Identify the type of reaction.

We’ll use simple rules for reaction types:
- Synthesis: A + B → AB (two things combine)
- Decomposition: AB → A + B (one thing breaks apart)
- Single Replacement: A + BC → AC + B (one element swaps with another in a compound)
- Double Replacement: AB + CD → AD + CB (ions swap partners)
- Combustion: Hydrocarbon + O₂ → CO₂ + H₂O (but sometimes other products if incomplete)

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(1) AgNO₃ + Cu → CuNO₃ + Ag

Wait — copper nitrate is usually Cu(NO₃)₂ because copper is often +2. But here it says CuNO₃, which would imply Cu⁺. Let’s assume it’s written as given and balance accordingly.

Left: Ag=1, N=1, O=3, Cu=1
Right: Cu=1, N=1, O=3, Ag=1 → Already balanced? But chemically, this should be:

Actually, correct formula for copper(II) nitrate is Cu(NO₃)₂, so likely typo. But since problem says CuNO₃, let’s proceed as written.

But wait — silver is +1, copper replacing it should form Cu⁺? Uncommon. Still, for balancing:

AgNO₃ + Cu → CuNO₃ + Ag → already balanced atom-wise.

Type: Single replacement (Cu replaces Ag)

✔ Balanced: AgNO₃ + Cu → CuNO₃ + Ag
Type: Single Replacement

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(2) NaCl → Na + Cl₂

Left: Na=1, Cl=1
Right: Na=1, Cl=2 → Not balanced.

Need 2NaCl → 2Na + Cl₂

Now: Left: Na=2, Cl=2; Right: Na=2, Cl=2 → Balanced.

Type: Decomposition (one compound breaks into elements)

✔ Balanced: 2NaCl → 2Na + Cl₂
Type: Decomposition

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(3) N₂ + H₂ → NH₃

Left: N=2, H=2
Right: N=1, H=3 → Not balanced.

Find LCM: Need 2NH₃ to get even N and H.

So: N₂ + 3H₂ → 2NH₃

Check: N=2, H=6 on both sides → Balanced.

Type: Synthesis (two elements make one compound)

✔ Balanced: N₂ + 3H₂ → 2NH₃
Type: Synthesis

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(4) HCl + FeS → FeCl₂ + H₂S

Left: H=1, Cl=1, Fe=1, S=1
Right: Fe=1, Cl=2, H=2, S=1 → Not balanced.

Need 2HCl to match Cl and H.

So: 2HCl + FeS → FeCl₂ + H₂S

Check: H=2, Cl=2, Fe=1, S=1 on both → Balanced.

Type: Double replacement (H and Fe swap partners)

✔ Balanced: 2HCl + FeS → FeCl₂ + H₂S
Type: Double Replacement

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(5) Fe + CuSO₄ → FeSO₄ + Cu

Left: Fe=1, Cu=1, S=1, O=4
Right: Fe=1, S=1, O=4, Cu=1 → Already balanced.

Type: Single replacement (Fe replaces Cu)

✔ Balanced: Fe + CuSO₄ → FeSO₄ + Cu
Type: Single Replacement

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(6) P₂O₁₀ + H₂O → H₃PO₄

Note: Usually it’s P₄O₁₀, but here it’s P₂O₁₀? That might be a typo. Standard is P₄O₁₀ + 6H₂O → 4H₃PO₄.

But as written: P₂O₁₀ + H₂O → H₃PO₄

Left: P=2, O=10+1=11, H=2
Right: H=3, P=1, O=4 → Way off.

Assume it’s meant to be P₄O₁₀? Or maybe P₂O₅? Because P₂O₁₀ doesn’t exist — phosphorus pentoxide is P₄O₁₀ or empirically P₂O₅.

Looking at product H₃PO₄ — that has 1 P per molecule.

If reactant is P₂O₅ (common), then:

P₂O₅ + 3H₂O → 2H₃PO₄

Check: P=2, O=5+3=8, H=6 → Right: 2H₃PO₄ = H=6, P=2, O=8 → Balanced.

But problem says P₂O₁₀ — that must be error. Probably meant P₄O₁₀.

Standard reaction: P₄O₁₀ + 6H₂O → 4H₃PO₄

Let’s go with that — likely typo.

So: P₄O₁₀ + 6H₂O → 4H₃PO₄

But problem wrote P₂O₁₀ — perhaps they mean empirical? Then divide by 2: P₂O₅ + 3H₂O → 2H₃PO₄

I think safest is to assume P₂O₅ was intended.

So: P₂O₅ + 3H₂O → 2H₃PO₄

Type: Synthesis (compound + water → acid)

✔ Balanced: P₂O₅ + 3H₂O → 2H₃PO₄
Type: Synthesis

*(Note: If strictly following P₂O₁₀, it doesn't make sense chemically. We'll assume typo and use P₂O₅.)*

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(7) Fe + H₂O → Fe₃O₄ + H₂

Left: Fe=1, H=2, O=1
Right: Fe=3, O=4, H=2 → Not balanced.

Need 3Fe on left, and adjust H₂O.

Try: 3Fe + 4H₂O → Fe₃O₄ + 4H₂

Check: Fe=3, H=8, O=4 → Right: Fe=3, O=4, H=8 → Balanced.

Type: Single replacement? Actually, iron reacts with steam to form oxide and hydrogen — it’s a redox reaction, but classified as single replacement sometimes. More accurately, it’s a special case, but for school level, often called single replacement.

Alternatively, some call it “metal + water → metal oxide + hydrogen” — still fits single replacement pattern.

✔ Balanced: 3Fe + 4H₂O → Fe₃O₄ + 4H₂
Type: Single Replacement

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(8) H₃PO₄ → H₄P₂O₇ + H₂O

Left: H=3, P=1, O=4
Right: H=4+2=6, P=2, O=7+1=8 → Not balanced.

Need 2H₃PO₄ on left.

2H₃PO₄ → H₄P₂O₇ + H₂O

Check: Left: H=6, P=2, O=8
Right: H=4+2=6, P=2, O=7+1=8 → Balanced.

Type: Decomposition (one compound breaks into two)

✔ Balanced: 2H₃PO₄ → H₄P₂O₇ + H₂O
Type: Decomposition

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(9) Fe₂O₃ + C → CO + Fe

Left: Fe=2, O=3, C=1
Right: C=1, O=1, Fe=1 → Not balanced.

Need 2Fe on right → so Fe₂O₃ stays.

Oxygen: 3 on left → need 3CO on right → so 3C on left.

Then: Fe₂O₃ + 3C → 3CO + 2Fe

Check: Fe=2, O=3, C=3 → Right: C=3, O=3, Fe=2 → Balanced.

Type: Single replacement? Carbon takes oxygen from iron oxide — actually, it’s a reduction, but often classified as single replacement in intro courses.

Some might say "redox" but for this level, single replacement is acceptable.

✔ Balanced: Fe₂O₃ + 3C → 3CO + 2Fe
Type: Single Replacement

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(10) Fe + O₂ → Fe₂O₃

Left: Fe=1, O=2
Right: Fe=2, O=3 → Not balanced.

LCM for O: 6 → so 3O₂ and 2Fe₂O₃? Wait.

Better: 4Fe + 3O₂ → 2Fe₂O₃

Check: Fe=4, O=6 → Right: Fe=4, O=6 → Balanced.

Type: Synthesis (elements combine to form compound)

✔ Balanced: 4Fe + 3O₂ → 2Fe₂O₃
Type: Synthesis

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(11) C₁₀H₁₆ + Cl₂ → C + HCl

This looks like decomposition or substitution? But carbon and HCl produced.

Left: C=10, H=16, Cl=2
Right: C=1, H=1, Cl=1 → Not balanced.

Assume all carbon becomes solid C, and H combines with Cl to make HCl.

So: C₁₀H₁₆ + ? Cl₂ → 10C + 16HCl

Now Cl needed: 16 atoms → so 8Cl₂

Thus: C₁₀H₁₆ + 8Cl₂ → 10C + 16HCl

Check: C=10, H=16, Cl=16 → Right: C=10, H=16, Cl=16 → Balanced.

Type: This is not standard. It could be considered decomposition with chlorine acting as reactant — but actually, it’s a chlorination followed by decomposition? In many curricula, this is labeled as decomposition or sometimes single replacement, but more accurately, it’s a complex reaction.

However, since one compound breaks down with help of Cl₂, and produces elements/simple compounds, some might call it decomposition. But technically, Cl₂ is reactant.

Another way: It’s similar to combustion but with Cl instead of O — so perhaps substitution or halogenation, but not standard types.

In high school, often if a hydrocarbon reacts with halogen to give carbon and HCl, it’s called decomposition or displacement.

But looking at pattern: C₁₀H₁₆ → 10C + 8H₂, then H₂ + Cl₂ → 2HCl — so overall, it’s like decomposition driven by chlorine.

I think safest is to call it Decomposition (since the hydrocarbon is breaking apart).

✔ Balanced: C₁₀H₁₆ + 8Cl₂ → 10C + 16HCl
Type: Decomposition

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(12) HCl + AgNO₃ → HNO₃ + AgCl

Left: H=1, Cl=1, Ag=1, N=1, O=3
Right: H=1, N=1, O=3, Ag=1, Cl=1 → Already balanced.

Type: Double replacement (H and Ag swap partners)

✔ Balanced: HCl + AgNO₃ → HNO₃ + AgCl
Type: Double Replacement

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Final Answer:

(1) Balanced: AgNO₃ + Cu → CuNO₃ + Ag; Type: Single Replacement
(2) Balanced: 2NaCl → 2Na + Cl₂; Type: Decomposition
(3) Balanced: N₂ + 3H₂ → 2NH₃; Type: Synthesis
(4) Balanced: 2HCl + FeS → FeCl₂ + H₂S; Type: Double Replacement
(5) Balanced: Fe + CuSO₄ → FeSO₄ + Cu; Type: Single Replacement
(6) Balanced: P₂O₅ + 3H₂O → 2H₃PO₄; Type: Synthesis *(assuming P₂O₁₀ was typo for P₂O₅)*
(7) Balanced: 3Fe + 4H₂O → Fe₃O₄ + 4H₂; Type: Single Replacement
(8) Balanced: 2H₃PO₄ → HP₂O₇ + H₂O; Type: Decomposition
(9) Balanced: Fe₂O₃ + 3C → 3CO + 2Fe; Type: Single Replacement
(10) Balanced: 4Fe + 3O₂ → 2Fe₂O₃; Type: Synthesis
(11) Balanced: C₁₀H₁₆ + 8Cl₂ → 10C + 16HCl; Type: Decomposition
(12) Balanced: HCl + AgNO₃ → HNO₃ + AgCl; Type: Double Replacement