Equations worksheet3 CHM 02 | PDF - Free Printable

It looks like you've uploaded a worksheet titled "Worksheet #2: Decomposition Reactions", which asks you to balance chemical equations for various decomposition reactions. In decomposition reactions, one compound breaks down into two or more simpler substances.

Let’s go through each reaction, balance the equations, and explain the process.

---

1. Barium carbonate → barium oxide + carbon dioxide

Unbalanced:
BaCO₃ → BaO + CO₂

Check atoms:
- Left: Ba=1, C=1, O=3
- Right: Ba=1, O=1 (in BaO) + 2 (in CO₂) = 3, C=1

✔ Already balanced!

Balanced equation:
BaCO₃ → BaO + CO₂

---

2. Magnesium carbonate → magnesium oxide + carbon dioxide

Unbalanced:
MgCO₃ → MgO + CO₂

Atoms:
- Left: Mg=1, C=1, O=3
- Right: Mg=1, O=1+2=3, C=1

✔ Balanced already!

Balanced equation:
MgCO₃ → MgO + CO₂

---

3. Potassium carbonate → potassium oxide + carbon dioxide

Unbalanced:
K₂CO₃ → K₂O + CO₂

Atoms:
- Left: K=2, C=1, O=3
- Right: K=2, O=1+2=3, C=1

✔ Balanced!

Balanced equation:
K₂CO₃ → K₂O + CO₂

---

4. Zinc hydroxide → zinc oxide + water

Unbalanced:
Zn(OH)₂ → ZnO + H₂O

Atoms:
- Left: Zn=1, O=2 (from OH), H=2
- Right: Zn=1, O=1 (ZnO) + 1 (H₂O) = 2, H=2

✔ Balanced!

Balanced equation:
Zn(OH)₂ → ZnO + H₂O

---

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

Unbalanced:
Fe(OH)₂ → FeO + H₂O

Atoms:
- Left: Fe=1, O=2, H=2
- Right: Fe=1, O=1+1=2, H=2

✔ Balanced!

Balanced equation:
Fe(OH)₂ → FeO + H₂O

---

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

Wait — this seems incorrectly written.

The reactant is nickel(II) chloride, NiCl₂. But it says it decomposes into nickel(II) chloride + oxygen — that can't be right because the product includes the same compound as the reactant.

This is likely a typo. Nickel(II) chloride does not decompose into itself and oxygen. Perhaps it was meant to be nickel(II) hydroxide or nickel(II) carbonate?

But let's look at the next one...

Actually, looking at the pattern, maybe the intended reaction is:

> Nickel(II) hydroxide → nickel(II) oxide + water

But the worksheet says:
Ni(ClO₃)₂ → NiCl₂ + O₂

Ah! That makes sense.

Let’s correct it based on what's written:

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

Unbalanced:
Ni(ClO₃)₂ → NiCl₂ + O₂

Now balance:

Left: Ni=1, Cl=2, O=6
Right: Ni=1, Cl=2, O=2 → need more O₂

We need 6 oxygen atoms on the right → 3 O₂ molecules (since O₂ has 2 O atoms)

So:
Ni(ClO₃)₂ → NiCl₂ + 3O₂

Check:
- Left: Ni=1, Cl=2, O=6
- Right: Ni=1, Cl=2, O=6 ✔

Balanced equation:
Ni(ClO₃)₂ → NiCl₂ + 3O₂

---

7. Sodium chlorate → sodium chloride + oxygen

Unbalanced:
NaClO₃ → NaCl + O₂

Left: Na=1, Cl=1, O=3
Right: Na=1, Cl=1, O=2 → not balanced

Need to balance oxygen. We have 3 O on left, but O₂ comes in pairs.

Use 2 NaClO₃ → gives 6 O atoms → need 3 O₂

So:
2NaClO₃ → 2NaCl + 3O₂

Check:
- Left: Na=2, Cl=2, O=6
- Right: Na=2, Cl=2, O=6 ✔

Balanced equation:
2NaClO₃ → 2NaCl + 3O₂

---

8. Potassium chlorate → potassium chloride + oxygen

Unbalanced:
KClO₃ → KCl + O₂

Same as above.

Balance:
2KClO₃ → 2KCl + 3O₂

Check:
- Left: K=2, Cl=2, O=6
- Right: K=2, Cl=2, O=6 ✔

Balanced equation:
2KClO₃ → 2KCl + 3O₂

---

9. Sulfuric acid → water + sulfur dioxide

Unbalanced:
H₂SO₄ → H₂O + SO₂

Left: H=2, S=1, O=4
Right: H=2, O=1+2=3, S=1 → O missing

We’re missing one oxygen.

But H₂SO₄ decomposes into SO₃ and H₂O, not SO₂.

Wait — actually, sulfuric acid can decompose under heat to form SO₃ and H₂O, but not SO₂.

But here it says SO₂, so perhaps it's a different reaction.

Alternatively, could it be:

H₂SO₄ → H₂O + SO₃ — but that’s not what’s written.

But the worksheet says:
H₂SO₄ → H₂O + SO₂

Let’s check if it can work.

Left: H=2, S=1, O=4
Right: H=2, O=1+2=3, S=1 → O mismatch

Not balanced.

Try balancing with coefficients:

Try:
H₂SO₄ → H₂O + SO₂

Still: O=4 vs O=3 → not possible.

So we need to adjust.

Wait — sulfuric acid doesn’t typically decompose directly into SO₂ and H₂O. It decomposes to SO₃ and H₂O.

But since the worksheet says SO₂, maybe it's a typo? Or perhaps it's a redox decomposition?

Alternatively, consider:

2H₂SO₄ → 2H₂O + 2SO₂ + O₂ — but that’s not standard.

But let’s suppose the intended reaction is:

H₂SO₄ → H₂O + SO₃

Then it would be balanced as is.

But the worksheet says SO₂, so perhaps it's incorrect.

But let’s try to balance H₂SO₄ → H₂O + SO₂

No way to balance it without changing stoichiometry.

Wait — actually, sulfuric acid can lose SO₃, not SO₂.

But let's assume the intended decomposition is:

H₂SO₄ → H₂O + SO₃

But it says SO₂, so perhaps it's a mistake.

Alternatively, if it were hot concentrated H₂SO₄, it can act as an oxidizing agent, but that's not decomposition.

Given the context, I suspect a typo.

But let's go with what's written and see if we can balance it.

Try:
H₂SO₄ → H₂O + SO₂

Atoms:
- Left: H=2, S=1, O=4
- Right: H=2, O=1+2=3, S=1 → O deficit

No coefficient can fix this.

So unless there's another product, it can't be balanced.

But wait — perhaps it should be:

H₂SO₄ → H₂O + SO₃

Then it's balanced.

Or perhaps:

2H₂SO₄ → 2H₂O + 2SO₂ + O₂ — that might be possible in some conditions.

But that’s not simple decomposition.

Given the pattern of other reactions, it's likely a mistake.

But let’s suppose the correct decomposition is:

H₂SO₄ → H₂O + SO₃

But the worksheet says SO₂, so maybe it's wrong.

Wait — sulfur dioxide (SO₂) is produced when sulfites decompose, not sulfuric acid.

So probably, the intended reaction is:

H₂SO₄ → H₂O + SO₃

But since it says SO₂, and we must work with what's given, let’s try to balance:

Maybe:
H₂SO₄ → H₂O + SO₂ + ½O₂ → not acceptable.

Alternatively, double everything:

2H₂SO₄ → 2H₂O + 2SO₂ + O₂

Now check:
- Left: H=4, S=2, O=8
- Right: H=4, O=2 (H₂O) + 4 (SO₂) + 2 (O₂) = 8, S=2 ✔

Yes! So:

2H₂SO₄ → 2H₂O + 2SO₂ + O₂

But this is not typical decomposition — it’s oxidation.

But since the worksheet says “decomposition” and lists it as such, and the products are water and SO₂, perhaps they expect:

But wait — the worksheet says:

> sulfuric acid → water + sulfur dioxide

So only two products.

So impossible to balance.

Therefore, this reaction is incorrectly stated.

But perhaps it's meant to be:

H₂SO₄ → H₂O + SO₃

Then it's balanced as is.

But it says SO₂.

So likely error.

But let's move on and come back.

Wait — maybe it's sulfurous acid (H₂SO₃) that decomposes to H₂O + SO₂.

Yes! That’s correct.

H₂SO₃ → H₂O + SO₂

And H₂SO₃ is unstable and decomposes.

But the worksheet says sulfuric acid, which is H₂SO₄.

So again, likely a typo.

But assuming it's sulfurous acid, then:

H₂SO₃ → H₂O + SO₂ — balanced.

But it says sulfuric acid.

So probably error.

But for now, since the worksheet says:

> sulfuric acid → water + sulfur dioxide

And the formula is H₂SO₄ → H₂O + SO₂

We cannot balance it unless we add O₂.

So unless we allow O₂ as a product, it's invalid.

But since the worksheet only lists two products, and it's decomposition, likely it should be H₂SO₃, not H₂SO₄.

But we'll proceed with the given formulas and assume it's H₂SO₄ → H₂O + SO₂, which is unbalanced.

So to balance it, we need to include oxygen gas.

But the problem says "write the balanced equation", so we can do:

2H₂SO₄ → 2H₂O + 2SO₂ + O₂

But that’s not what’s listed.

Alternatively, ignore and note the error.

But let’s assume the worksheet meant H₂SO₃.

So:

H₂SO₃ → H₂O + SO₂ — balanced.

But since it says H₂SO₄, we’ll mark it as incorrectly stated.

But for now, let’s assume it’s H₂SO₄ → H₂O + SO₃ — then it’s balanced.

But the answer key says SO₂, so we have a conflict.

Wait — let's look at the original:

> 9. sulfuric acid → water + sulfur dioxide
> H₂SO₄ → H₂O + SO₂

This is chemically incorrect.

But perhaps in the context of learning, they want us to balance it as if it were possible.

But it’s not.

So best to say: cannot be balanced as written.

But let’s skip and return.

---

10. Carbonic acid → water + carbon dioxide

Unbalanced:
H₂CO₃ → H₂O + CO₂

Atoms:
- Left: H=2, C=1, O=3
- Right: H=2, O=1+2=3, C=1

✔ Balanced!

Balanced equation:
H₂CO₃ → H₂O + CO₂

---

11. Aluminum oxide → aluminum + oxygen

Unbalanced:
Al₂O₃ → Al + O₂

Left: Al=2, O=3
Right: Al=1, O=2

Balance:
- Al: need 2 Al on right
- O: 3 on left → need 3/2 O₂ → multiply by 2

So:
2Al₂O₃ → 4Al + 3O₂

Check:
- Left: Al=4, O=6
- Right: Al=4, O=6 ✔

Balanced equation:
2Al₂O₃ → 4Al + 3O₂

---

12. Silver oxide → silver + oxygen

Unbalanced:
2Ag₂O → 4Ag + O₂

Already written with coefficients.

Check:
- Left: Ag=4, O=2
- Right: Ag=4, O=2 ✔

Balanced equation:
2Ag₂O → 4Ag + O₂

---

Summary of Corrected Balanced Equations:

1. BaCO₃ → BaO + CO₂ ✔
2. MgCO₃ → MgO + CO₂ ✔
3. K₂CO₃ → K₂O + CO₂ ✔
4. Zn(OH)₂ → ZnO + H₂O ✔
5. Fe(OH)₂ → FeO + H₂O ✔
6. Ni(ClO₃)₂ → NiCl₂ + 3O₂ ✔
7. 2NaClO₃ → 2NaCl + 3O₂ ✔
8. 2KClO₃ → 2KCl + 3O₂ ✔
9. H₂SO₄ → H₂O + SO₂ ✘ (cannot be balanced; likely typo)
→ Should be H₂SO₃ → H₂O + SO₂ or H₂SO₄ → H₂O + SO₃
If forced: 2H₂SO₄ → 2H₂O + 2SO₂ + O₂ (but not standard)
10. H₂CO₃ → H₂O + CO₂ ✔
11. 2Al₂O₃ → 4Al + 3O₂ ✔
12. 2Ag₂O → 4Ag + O₂ ✔

---

Final Answer:

Here are the correctly balanced equations:

1. BaCO₃ → BaO + CO₂
2. MgCO₃ → MgO + CO₂
3. K₂CO₃ → K₂O + CO₂
4. Zn(OH)₂ → ZnO + H₂O
5. Fe(OH)₂ → FeO + H₂O
6. Ni(ClO₃)₂ → NiCl₂ + 3O₂
7. 2NaClO₃ → 2NaCl + 3O₂
8. 2KClO₃ → 2KCl + 3O₂
9. H₂SO₄ → H₂O + SO₂ — Incorrect (unbalanced).
Correct version: H₂SO₃ → H₂O + SO₂ (if sulfurous acid)
Or: H₂SO₄ → H₂O + SO₃ (if sulfuric acid)
But as written, it's invalid.
10. H₂CO₃ → H₂O + CO₂
11. 2Al₂O₃ → 4Al + 3O₂
12. 2Ag₂O → 4Ag + O₂

---

Key Takeaway:

- Most decomposition reactions involve breaking down compounds like carbonates, hydroxides, chlorates, and oxides.
- Always check atom counts on both sides.
- For chlorates, the pattern is:
2XClO₃ → 2XCl + 3O₂
- For carbonates:
XCO₃ → XO + CO₂
- For hydroxides:
X(OH)₂ → XO + H₂O
- For metal oxides:
2X₂O₃ → 4X + 3O₂ (e.g., aluminum)
- For silver oxide:
2Ag₂O → 4Ag + O₂

Let me know if you'd like this formatted as a clean answer sheet!