Equations worksheet3 CHM 02 | PDF - Free Printable

Actually, you did not upload an image — you pasted the text of “Worksheet #2: Decomposition Reactions” directly into your message. That’s perfectly fine! I’ll solve and explain the task based on the text you provided.

---

## ✔ TASK: Analyze the 12 decomposition reactions listed.

The goal is likely to:
- Confirm they are decomposition reactions.
- Check if they are balanced.
- Understand what each reaction represents.

---

🧪 What is a Decomposition Reaction?

A decomposition reaction is a chemical reaction in which one compound breaks down into two or more simpler substances.

General form:
AB → A + B

---

Let’s go through each reaction one by one:

---

1. Barium carbonate → barium oxide + carbon dioxide

BaCO₃ → BaO + CO₂

✔ Balanced? Yes.
Left: Ba=1, C=1, O=3
Right: Ba=1, O=1 (in BaO) + 2 (in CO₂) = 3; C=1
✔ Decomposition? Yes — one compound → two compounds.

---

2. Magnesium carbonate → magnesium oxide + carbon dioxide

MgCO₃ → MgO + CO₂

✔ Balanced? Yes.
✔ Decomposition? Yes.

---

3. Potassium carbonate → potassium oxide + carbon dioxide

K₂CO₃ → K₂O + CO₂

✔ Balanced? Yes.
Left: K=2, C=1, O=3
Right: K=2, O=1 (K₂O) + 2 (CO₂) = 3; C=1
✔ Decomposition? Yes.

---

4. Zinc hydroxide → zinc oxide + water

Zn(OH)₂ → ZnO + H₂O

✔ Balanced? Yes.
Left: Zn=1, O=2, H=2
Right: Zn=1, O=1 (ZnO) + 1 (H₂O) = 2; H=2
✔ Decomposition? Yes.

---

5. Iron(II) hydroxide → iron(II) oxide + water

Fe(OH)₂ → FeO + H₂O

✔ Balanced? Yes.
Left: Fe=1, O=2, H=2
Right: Fe=1, O=1 (FeO) + 1 (H₂O) = 2; H=2
✔ Decomposition? Yes.

---

6. Nickel(II) chlorate → nickel(II) chloride + oxygen

Ni(ClO₃)₂ → NiCl₂ + 3O₂

⚠️ Wait — this is NOT balanced as written!

Original:
Ni(ClO₃)₂ → NiCl₂ + O₂ ← This is unbalanced!

Let’s fix it:

- Left: Ni=1, Cl=2, O=6
- Right: Ni=1, Cl=2, O=2 → need 6 oxygen atoms → so we need 3O₂

✔ Correct balanced equation:
Ni(ClO₃)₂ → NiCl₂ + 3O₂

✔ Decomposition? Yes — one compound → two products.

---

7. Sodium chlorate → sodium chloride + oxygen

2NaClO₃ → 2NaCl + 3O₂

✔ Balanced? Let’s check:
Left: Na=2, Cl=2, O=6
Right: Na=2, Cl=2, O=6 (from 3O₂)
✔ Decomposition? Yes.

*(Note: The coefficient "2" is needed to balance oxygen atoms.)*

---

8. Potassium chlorate → potassium chloride + oxygen

2KClO₃ → 2KCl + 3O₂

✔ Balanced? Yes — same logic as #7.
✔ Decomposition? Yes.

---

9. Sulfuric acid → water + sulfur trioxide

H₂SO₄ → H₂O + SO₃

✔ Balanced? Yes.
Left: H=2, S=1, O=4
Right: H=2, O=1 (H₂O) + 3 (SO₃) = 4; S=1
✔ Decomposition? Yes — though this is a reversible reaction under heat.

---

10. Carbonic acid → water + carbon dioxide

H₂CO₃ → H₂O + CO₂

✔ Balanced? Yes.
✔ Decomposition? Yes — very common; happens when you open a soda!

---

11. Aluminum oxide → aluminum + oxygen

2Al₂O₃ → 4Al + 3O₂

✔ Balanced? Yes.
Left: Al=4, O=6
Right: Al=4, O=6 (3O₂)
✔ Decomposition? Yes — requires electrolysis (high energy).

---

12. Silver oxide → silver + oxygen

2Ag₂O → 4Ag + O₂

✔ Balanced? Yes.
Left: Ag=4, O=2
Right: Ag=4, O=2
✔ Decomposition? Yes — occurs upon heating.

---

## ✍️ Summary & Corrections

All 12 reactions are decomposition reactions, but two were unbalanced as originally written:

- #6: Should be Ni(ClO₃)₂ → NiCl₂ + 3O₂ (not just O₂)
- #7, #8, #11, #12 already have correct coefficients for balancing.

---

## 📌 Final Answer:

✔ All 12 reactions are decomposition reactions.

⚠️ Only reaction #6 was incorrectly written — it must include 3O₂ to be balanced.

✔ All others are correctly balanced and classified.

---

## 💡 Teaching Tip:

When balancing decomposition reactions involving oxyanions like chlorate (ClO₃⁻), remember that oxygen often forms O₂ gas, so you may need to multiply to get even numbers of oxygen atoms.

Example:
ClO₃⁻ has 3 oxygen atoms → to make O₂, you need multiples of 2 oxygen atoms → so 2 ClO₃⁻ gives 6 oxygen atoms → 3 O₂ molecules.

---

Let me know if you’d like to practice writing these from word equations or predicting products! 😊