Balancing Act worksheet for practicing balancing chemical equations with step-by-step instructions and examples.

You’ve uploaded a worksheet titled “Balancing Act”, which teaches how to balance chemical equations using coefficients. The core idea is the Law of Conservation of Mass: atoms are neither created nor destroyed in a chemical reaction, so the number of each type of atom must be equal on both sides (reactants and products).

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## ✔ Step-by-Step Explanation

🔹 Part 1: Example — Magnesium + Oxygen → Magnesium Oxide

Given unbalanced equation:
> Mg + O₂ → MgO

Atoms present:
- Left (Reactants): Mg = 1, O = 2
- Right (Products): Mg = 1, O = 1 ← Not balanced!

To balance oxygen, we need 2 oxygen atoms on the right → put coefficient 2 in front of MgO:
> Mg + O₂ → 2MgO

Now check atoms:
- Mg: 1 on left, 2 on right → not balanced!
- O: 2 on left, 2 on right → balanced.

So now fix magnesium: put 2 in front of Mg on left:
> 2Mg + O₂ → 2MgO

✔ Final balanced equation:
> 2Mg + O₂ → 2MgO

Atoms:
- Mg: 2 = 2
- O: 2 = 2 ✔️

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## 🧪 Now, let’s solve the “Try these” problems:

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1. Ca + O₂ → CaO

Unbalanced:
- Ca: 1 = 1
- O: 2 ≠ 1 → not balanced.

Put 2 in front of CaO:
> Ca + O₂ → 2CaO

Now:
- Ca: 1 ≠ 2
- O: 2 = 2

Fix Ca: put 2 in front of Ca:
> 2Ca + O₂ → 2CaO

✔ Balanced!

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2. HgO → Hg + O₂

Unbalanced:
- Hg: 1 = 1
- O: 1 ≠ 2

We need even number of O on left → put 2 in front of HgO:
> 2HgO → Hg + O₂

Now:
- Hg: 2 ≠ 1
- O: 2 = 2

Fix Hg: put 2 in front of Hg:
> 2HgO → 2Hg + O₂

✔ Balanced!

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3. Mg + N₂ → Mg₃N₂

Unbalanced:
- Mg: 1 ≠ 3
- N: 2 = 2

Put 3 in front of Mg:
> 3Mg + N₂ → Mg₃N₂

Check:
- Mg: 3 = 3
- N: 2 = 2

✔ Balanced!

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4. B + O₂ → B₂O₃

Unbalanced:
- B: 1 ≠ 2
- O: 2 ≠ 3

We need to make atoms match. Use LCM method.

Oxygen: 2 on left, 3 on right → LCM of 2 and 3 is 6.

So:
- Put 3 in front of O₂ → 3×O₂ = 6 O atoms
- Put 2 in front of B₂O₃ → 2×B₂O₃ = 4 B and 6 O atoms

Now equation:
> B + 3O₂ → 2B₂O₃

Balance B: 4 B needed on left → put 4 in front of B:
> 4B + 3O₂ → 2B₂O₃

✔ Check:
- B: 4 = 4
- O: 6 = 6 ✔️

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5. CuO + H₂ → Cu + H₂O

Unbalanced:
- Cu: 1 = 1
- O: 1 = 1
- H: 2 = 2 → Wait, looks balanced?

Let’s double-check:

Left: Cu=1, O=1, H=2
Right: Cu=1, O=1, H=2

✔ Actually, this equation is already balanced!

> CuO + H₂ → Cu + H₂O

No coefficients needed.

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## ✔ Final Answers:

1. 2Ca + O₂ → 2CaO
2. 2HgO → 2Hg + O₂
3. 3Mg + N₂ → Mg₃N₂
4. 4B + 3O₂ → 2B₂O₃
5. CuO + H₂ → Cu + H₂O *(already balanced)*

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## 💡 Tips for Balancing Equations:

- Start with elements that appear only once per side.
- Save hydrogen and oxygen for last if possible (they often appear in multiple compounds).
- Never change subscripts — only use coefficients!
- Double-check atom counts after adding coefficients.

Let me know if you’d like to practice more or see visual diagrams! 😊