Tvpes of Reactions Worksheet Given the | StudyX - Free Printable

Let's go through the Types of Reactions Worksheet step by step, identifying the type of reaction, balancing each equation, and answering the final two questions based on the molecular diagram.

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1) K + Cl₂ → KCl

- Type of Reaction: Synthesis (S) – Two elements combine to form a compound.
- Balanced Equation:
- Unbalanced: K + Cl₂ → KCl
- Balance Cl: 2K + Cl₂ → 2KCl
- ✔ Answer:
2K + Cl₂ → 2KCl
Type: S

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2) NH₃ → N₂ + H₂

- Type of Reaction: Decomposition (D) – One compound breaks down into simpler substances.
- Balanced Equation:
- Unbalanced: NH₃ → N₂ + H₂
- Balance N: 2NH₃ → N₂ + ...
- Balance H: 2NH₃ → N₂ + 3H₂
- ✔ Answer:
2NH₃ → N₂ + 3H₂
Type: D

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3) NaF + Br₂ → NaBr + F₂

- Type of Reaction: Single Replacement (SR) – A more reactive element replaces another in a compound.
- Br₂ is more reactive than F₂? No — actually, fluorine is more reactive than bromine, so this reaction won't happen as written, but we classify it based on form.
- Still, the pattern is: halogen replacing halogen → single replacement.
- Balanced Equation:
- NaF + Br₂ → NaBr + F₂
- Need 2NaF and 2NaBr for balance:
- 2NaF + Br₂ → 2NaBr + F₂
- ✔ Answer:
2NaF + Br₂ → 2NaBr + F₂
Type: SR

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4) SO₂ + Li₂Se → SSe₂ + Li₂O

- Type of Reaction: Double Replacement (DR) – Ions exchange between two compounds.
- SO₂ is not an ionic compound, but here it's treated as a reactant forming a new compound.
- Actually, this looks like a double displacement, but let’s check if it makes sense chemically.
- But SO₂ is covalent; Li₂Se is ionic. This might be a metathesis-like reaction, but not typical.
- However, based on the form: AB + CD → AD + CB → Double Replacement.
- Balanced Equation:
- SO₂ + Li₂Se → SSe₂ + Li₂O
- Already balanced? Check atoms:
- Left: S=1, O=2, Li=2, Se=1
- Right: S=1, Se=2, Li=2, O=1 → Not balanced!
- So need to balance:
- 2SO₂ + 2Li₂Se → SSe₂ + 2Li₂O? No — still wrong.
- Try: SO₂ + Li₂Se → SSe₂ + Li₂O — doesn’t work.
- Wait — maybe:
SO₂ + Li₂Se → SSe₂ + Li₂O → needs 2 SO₂ and 2 Li₂Se?
Let’s try:
- 2SO₂ + 2Li₂Se → SSe₂ + 2Li₂O + ? — too many S and O.
- Better: Maybe it’s not balanced unless we adjust stoichiometry.
- Actually, this reaction isn’t realistic, but for balancing:
- We have: SO₂ + Li₂Se → SSe₂ + Li₂O
- S: 1 = 1 → OK
- O: 2 = 1 → need 2 Li₂O → so 2Li₂O
- Then Li: 2 → 4 → need 2Li₂Se
- Se: 2 → 2 → OK
- Now S: left has 1 from SO₂, right has 1 from SSe₂ → OK
- But O: 2 from SO₂ → 2 from 2Li₂O → OK
- So:
SO₂ + 2Li₂Se → SSe₂ + 2Li₂O — wait, now Se: left = 2, right = 2 → OK
But S: left = 1, right = 1 → OK
O: left = 2, right = 2 → OK
Li: left = 4, right = 4 → OK
- But we have only one SO₂, yet need 2Li₂Se → yes.
- But SSe₂ has one S, so SO₂ provides one S → OK
- So:
SO₂ + 2Li₂Se → SSe₂ + 2Li₂O
- ✔ Answer:
SO₂ + 2Li₂Se → SSe₂ + 2Li₂O
Type: DR

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5) PbSO₄ → PbSO₃ + O₂

- Type of Reaction: Decomposition (D) – One compound breaks down.
- Balanced Equation:
- PbSO₄ → PbSO₃ + O₂
- Check atoms:
- Pb: 1 = 1
- S: 1 = 1
- O: 4 → 3 + 2 = 5 → not balanced
- So need to balance:
- 2PbSO₄ → 2PbSO₃ + O₂
- O: left = 8, right = 6 + 2 = 8 → OK
- All others balanced.
- ✔ Answer:
2PbSO₄ → 2PbSO₃ + O₂
Type: D

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6) Al + Fe₂O₃ → Fe + Al₂O₃

- Type of Reaction: Single Replacement (SR) – Aluminum displaces iron.
- Balanced Equation:
- Al + Fe₂O₃ → Fe + Al₂O₃
- Balance Fe: 2Fe → so 2Fe on right
- Balance Al: Al₂O₃ has 2Al → so 2Al on left
- O: 3 on both sides
- So:
2Al + Fe₂O₃ → 2Fe + Al₂O₃
- ✔ Answer:
2Al + Fe₂O₃ → 2Fe + Al₂O₃
Type: SR

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7) SF₆ → S + F₂

- Type of Reaction: Decomposition (D)
- Balanced Equation:
- SF₆ → S + F₂
- F: 6 → need 3F₂
- So: SF₆ → S + 3F₂
- ✔ Answer:
SF₆ → S + 3F₂
Type: D

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8) C₂H₄ + O₂ → CO₂ + H₂O

- Type of Reaction: Combustion (C) – Hydrocarbon burns in oxygen.
- Balanced Equation:
- C₂H₄ + O₂ → 2CO₂ + 2H₂O
- C: 2 → 2 → OK
- H: 4 → 4 → OK
- O: 2 → 4 (from CO₂) + 2 (from H₂O) = 6 → so need 3O₂
- So: C₂H₄ + 3O₂ → 2CO₂ + 2H₂O
- ✔ Answer:
C₂H₄ + 3O₂ → 2CO₂ + 2H₂O
Type: C

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9) KClO₃ → KCl + O₂

- Type of Reaction: Decomposition (D)
- Balanced Equation:
- KClO₃ → KCl + O₂
- O: 3 → need 3/2 O₂ → so use fractions or multiply
- Multiply by 2:
2KClO₃ → 2KCl + 3O₂
- ✔ Answer:
2KClO₃ → 2KCl + 3O₂
Type: D

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10) Pb(NO₃)₂ + NaCl → NaNO₃ + PbCl₂

- Type of Reaction: Double Replacement (DR)
- Balanced Equation:
- Pb(NO₃)₂ + NaCl → NaNO₃ + PbCl₂
- Pb: 1 = 1
- NO₃: 2 → need 2NaNO₃
- Na: 2 → need 2NaCl
- Cl: 2 → 2 → OK
- So:
Pb(NO₃)₂ + 2NaCl → 2NaNO₃ + PbCl₂
- ✔ Answer:
Pb(NO₃)₂ + 2NaCl → 2NaNO₃ + PbCl₂
Type: DR

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11) What type of reaction is shown to the left?

We see a diagram:

- One molecule: black circle (carbon) bonded to two white circles (oxygen) → CO₂
- Plus one molecule: two white circles (O₂)
- Product: one molecule with one carbon and three oxygens → CO₂? Wait, no — look again.

Wait, let's interpret the diagram carefully.

From the image description:

> Black = Carbon, White = Oxygen

The diagram shows:

- Reactants:
- One molecule: one black (C) and two white (O) → CO₂
- One molecule: two white (O) → O₂
- Products:
- One molecule: one black (C) and three white (O) → CO₃? But that's not stable.
- Wait — perhaps it's CO₂ + O₂ → CO₂? That can't be.

Wait — actually, re-examining:

It says:

> ● = Oxygen
> ●● = Carbon

But then shows:

- Left: one black circle (C) with two white circles (O) → CO₂
- Plus: one molecule with two white circles → O₂
- Arrow to: one molecule with one black and three white → CO₃? Not possible.

Wait — perhaps it's:

- Carbon monoxide + oxygen → carbon dioxide?

But the diagram shows:

- One molecule: C (black) + one O (white) → CO
- Plus O₂ → two O atoms
- Product: C + two O → CO₂

Ah! That makes sense.

So likely:

- Reactants: CO + O₂
- Product: CO₂

But the diagram shows:

- Left: one black (C) and one white (O) → CO
- Plus: two white circles → O₂
- Right: one black and two white → CO₂

But that’s not balanced — CO + O₂ → CO₂ has unbalanced O.

Actually, correct reaction:
2CO + O₂ → 2CO₂

But the diagram shows only one CO + one O₂ → one CO₂ — which is unbalanced.

But the question asks: What type of reaction is shown?

Even if unbalanced, the form is:
CO + O₂ → CO₂ → combustion of carbon monoxide.

So it's a combustion reaction.

Also, it involves a compound reacting with oxygen to produce another compound — combustion.

✔ Answer:
Combustion (C)

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12) Using the key provided, write the complete chemical formula shown in the box above:

From the diagram:

- Reactants:
- Molecule 1: one carbon (black), one oxygen (white) → CO
- Molecule 2: two oxygens → O₂
- Product: one carbon, two oxygens → CO₂

So:
CO + O₂ → CO₂

But this is unbalanced.

✔ Answer:
CO + O₂ → CO₂

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13) Now balance the equation above so that both sides are equal.

Unbalanced: CO + O₂ → CO₂

Balance:
- C: 1 = 1 → OK
- O: 1 + 2 = 3 on left, 2 on right → not balanced
- Try 2CO + O₂ → 2CO₂
- C: 2 = 2
- O: 2 + 2 = 4 on left, 4 on right → OK

✔ Answer:
2CO + O₂ → 2CO₂

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## ✔ Final Answers:

| # | Balanced Equation | Type |
|---|-------------------|------|
| 1 | 2K + Cl₂ → 2KCl | S |
| 2 | 2NH₃ → N₂ + 3H₂ | D |
| 3 | 2NaF + Br₂ → 2NaBr + F₂ | SR |
| 4 | SO₂ + 2Li₂Se → SSe₂ + 2Li₂O | DR |
| 5 | 2PbSO₄ → 2PbSO₃ + O₂ | D |
| 6 | 2Al + Fe₂O₃ → 2Fe + Al₂O₃ | SR |
| 7 | SF₆ → S + 3F₂ | D |
| 8 | C₂H₄ + 3O₂ → 2CO₂ + 2H₂O | C |
| 9 | 2KClO₃ → 2KCl + 3O₂ | D |
|10 | Pb(NO₃)₂ + 2NaCl → 2NaNO₃ + PbCl₂ | DR |
|11 | Combustion (C) |
|12 | CO + O₂ → CO₂ |
|13 | 2CO + O₂ → 2CO₂ |

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