Types of Reactions Worksheet Given the | StudyX - Free Printable

Let’s go through each reaction one by one, identify the type of reaction, and then balance it.

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1) ___ K + ___ Cl₂ → ___ KCl

- Type of Reaction: Synthesis (S)
*Two elements combine to form a single compound.*

- Balancing:
Left: K = 1, Cl = 2
Right: K = 1, Cl = 1 → need 2 KCl to balance Cl
So: 2K + Cl₂ → 2KCl

✔ Balanced Equation: 2 K + 1 Cl₂ → 2 KCl
*(Coefficients: 2, 1, 2)*

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2) ___ NH₃ → ___ N₂ + ___ H₂

- Type of Reaction: Decomposition (D)
*One compound breaks down into two or more simpler substances.*

- Balancing:
Left: N=1, H=3
Right: N=2, H=2 → need to make atoms equal
Try: 2NH₃ → N₂ + 3H₂
Check: N: 2=2, H: 6=6 → balanced!

✔ Balanced Equation: 2 NH₃ → 1 N₂ + 3 H₂
*(Coefficients: 2, 1, 3)*

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3) ___ NaF + ___ Br₂ → ___ NaBr + ___ F₂

- Type of Reaction: Single Replacement (SR)
*One element replaces another in a compound. Here, Br replaces F in NaF.*
*(Note: This reaction is not actually favorable in reality — fluorine is more reactive than bromine — but for classification purposes, we treat it as written.)*

- Balancing:
Left: Na=1, F=1, Br=2
Right: Na=1, Br=1, F=2 → need 2NaF and 2NaBr
So: 2NaF + Br₂ → 2NaBr + F₂

✔ Balanced Equation: 2 NaF + 1 Br₂ → 2 NaBr + 1 F₂
*(Coefficients: 2, 1, 2, 1)*

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4) ___ SO₂ + ___ Li₂Se → ___ SSe₂ + ___ Li₂O

- Type of Reaction: Double Replacement (DR)
*Ions swap partners: SO₂ and Li₂Se exchange parts to form SSe₂ and Li₂O.*

- Balancing:
Left: S=1, O=2, Li=2, Se=1
Right: S=1, Se=2, Li=2, O=1 → need to balance O and Se
Try: 2SO₂ + 2Li₂Se → SSe₂ + 2Li₂O? Wait — SSe₂ has 1 S and 2 Se, so we need 2 Se on left → 2Li₂Se gives 2 Se.
But now S: left has 2 (from 2SO₂), right has only 1 (in SSe₂).
So try: 2SO₂ + 2Li₂Se → 2SSe₂ + 2Li₂O? Now S: 2=2, Se: 2=4 → nope.
Better: Let’s look at atoms:

Actually, let's reassign:

We want:
SO₂ + Li₂Se → SSe₂ + Li₂O

Balance Se: need 2 Li₂Se → gives 2 Se → need 1 SSe₂ (has 2 Se) → good.
Now S: 1 from SO₂, 1 in SSe₂ → good.
O: 2 from SO₂ → need 2 Li₂O → that gives 2 O → good.
Li: 4 from 2Li₂Se → 4 in 2Li₂O → good.

So: 1 SO₂ + 2 Li₂Se → 1 SSe₂ + 2 Li₂O

✔ Balanced Equation: 1 SO₂ + 2 Li₂Se → 1 SSe₂ + 2 Li₂O
*(Coefficients: 1, 2, 1, 2)*

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5) ___ PbSO₄ → ___ PbSO₃ + ___ O₂

- Type of Reaction: Decomposition (D)
*One compound breaks down into two products.*

- Balancing:
Left: Pb=1, S=1, O=4
Right: Pb=1, S=1, O=3+2=5 → too many O on right? Wait — PbSO₃ has 3 O, O₂ has 2 → total 5 O. Left has 4 O → imbalance.

Actually, this reaction doesn’t make sense chemically — PbSO₄ doesn’t decompose to PbSO₃ and O₂ under normal conditions. But assuming it’s written as is, we must balance atoms.

Let’s try: 2PbSO₄ → 2PbSO₃ + O₂
Left: Pb=2, S=2, O=8
Right: Pb=2, S=2, O=6 (from 2PbSO₃) + 2 (from O₂) = 8 → balanced!

✔ Balanced Equation: 2 PbSO₄ → 2 PbSO₃ + 1 O₂
*(Coefficients: 2, 2, 1)*

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6) ___ Al + ___ Fe₂O₃ → ___ Fe + ___ Al₂O₃

- Type of Reaction: Single Replacement (SR)
*Aluminum replaces iron in iron(III) oxide — classic thermite reaction.*

- Balancing:
Left: Al=1, Fe=2, O=3
Right: Fe=1, Al=2, O=3 → need to balance Fe and Al
Use: 2Al + Fe₂O₃ → 2Fe + Al₂O₃
Check: Al: 2=2, Fe: 2=2, O: 3=3 → perfect!

✔ Balanced Equation: 2 Al + 1 Fe₂O₃ → 2 Fe + 1 Al₂O₃
*(Coefficients: 2, 1, 2, 1)*

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7) ___ SF₆ → ___ S + ___ F₂

- Type of Reaction: Decomposition (D)
*One compound breaks into its elements.*

- Balancing:
Left: S=1, F=6
Right: S=1, F=2 → need 3 F₂ to get 6 F
So: SF₆ → S + 3F₂

✔ Balanced Equation: 1 SF₆ → 1 S + 3 F₂
*(Coefficients: 1, 1, 3)*

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8) ___ C₂H₄ + ___ O₂ → ___ CO₂ + ___ H₂O

- Type of Reaction: Combustion (C)
*Hydrocarbon reacts with oxygen to produce CO₂ and H₂O.*

- Balancing:
Left: C=2, H=4, O=2
Right: C=1 (in CO₂), H=2 (in H₂O) → need 2CO₂ and 2H₂O
Now: C₂H₄ + O₂ → 2CO₂ + 2H₂O
Right: C=2, H=4, O=4+2=6 → need 3 O₂ on left (since 3×2=6 O)

✔ Balanced Equation: 1 C₂H₄ + 3 O₂ → 2 CO₂ + 2 H₂O
*(Coefficients: 1, 3, 2, 2)*

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## ✔ Final Answers Summary:

| # | Balanced Equation | Type |
|---|---------------------------------------------|------|
| 1 | 2 K + 1 Cl₂ → 2 KCl | S |
| 2 | 2 NH₃ → 1 N₂ + 3 H₂ | D |
| 3 | 2 NaF + 1 Br₂ → 2 NaBr + 1 F₂ | SR |
| 4 | 1 SO₂ + 2 Li₂Se → 1 SSe₂ + 2 Li₂O | DR |
| 5 | 2 PbSO₄ → 2 PbSO₃ + 1 O₂ | D |
| 6 | 2 Al + 1 Fe₂O₃ → 2 Fe + 1 Al₂O₃ | SR |
| 7 | 1 SF₆ → 1 S + 3 F₂ | D |
| 8 | 1 C₂H₄ + 3 O₂ → 2 CO₂ + 2 H₂O | C |

*(S = Synthesis, D = Decomposition, SR = Single Replacement, DR = Double Replacement, C = Combustion)*

Let me know if you’d like explanations for any specific reaction!