Student completing a redox reactions chemistry worksheet.

You're looking at a Redox Reactions worksheet — likely designed for GCSE Chemistry (Topic 4: Chemical Changes). Since you’ve asked to “solve the problem and explain the solution,” I’ll walk you through how to complete the visible parts of the worksheet based on standard redox chemistry principles.

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## 🔍 PART 1: MATCHING DEFINITIONS (Launch Section)

The worksheet asks you to match boxes on the right to define oxidation and reduction.

The options are:
- Loss of electrons
- Gain of electrons
- Loss of oxygen
- Gain of oxygen

✔ Correct Matching:

> Oxidation = Loss of electrons
> Reduction = Gain of electrons

*(This is the modern, electron-transfer definition used in most curricula today.)*

> Oxidation = Loss of oxygen *(older definition, still useful for some reactions)*
> Reduction = Gain of oxygen *(older definition)*

💡 Important Note: In modern chemistry, we use the electron transfer definitions as primary because they apply universally — even in reactions without oxygen!

So if you’re matching to "define oxidation and reduction", you can pair both sets:

- Oxidation → Loss of electrons / Loss of oxygen
- Reduction → Gain of electrons / Gain of oxygen

But typically, exams expect you to know that:
> Oxidation = loss of electrons
> Reduction = gain of electrons

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## 🧪 PART 2: WRITING HALF-EQUATIONS (Table Section)

You’re given several overall redox reactions and asked to write the reduction half-equation for each.

Let’s go one by one.

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1. Overall Reaction:

CuO + Mg → MgO + Cu

➡️ Identify what’s being reduced:
Copper goes from +2 in CuO to 0 in Cu → so Cu²⁺ gains 2 electrons → Cu

✔ Reduction Half-Equation:
Cu²⁺ + 2e⁻ → Cu

*(Note: You may also see this written with CuO, but since it’s an ionic half-equation, we use ions.)*

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2. Overall Reaction:

Fe₂O₃ + 2Al → 2Fe + Al₂O₃

➡️ Iron goes from +3 in Fe₂O₃ to 0 in Fe → so Fe³⁺ gains 3 electrons → Fe

✔ Reduction Half-Equation:
Fe³⁺ + 3e⁻ → Fe

*(Note: Since there are 2 Fe atoms, you might think to multiply, but half-equations are written per ion/atom unless specified otherwise.)*

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3. Overall Reaction:

CuSO₄ + Zn → ZnSO₄ + Cu

➡️ Copper goes from +2 in CuSO₄ to 0 in Cu → so Cu²⁺ + 2e⁻ → Cu

✔ Reduction Half-Equation:
Cu²⁺ + 2e⁻ → Cu

*(Same as reaction #1 — copper is being reduced again.)*

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4. Overall Reaction:

2KBr + Cl₂ → 2KCl + Br₂

➡️ Chlorine goes from 0 in Cl₂ to -1 in KCl → so Cl₂ gains electrons → 2Cl⁻

✔ Reduction Half-Equation:
Cl₂ + 2e⁻ → 2Cl⁻

*(Note: Here, chlorine is being reduced — it gains electrons. Bromine is oxidized.)*

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5. (Partially visible) Likely:

Cl₂ + 2NaF → ???
*(This reaction doesn’t actually occur — fluorine is more reactive than chlorine, so Cl₂ cannot displace F⁻. But if the worksheet says to write it, perhaps it's hypothetical or misprinted.)*

If forced to write reduction half-equation assuming Cl₂ is reduced:

✔ Cl₂ + 2e⁻ → 2Cl⁻
*(Same as above.)*

But scientifically, this reaction doesn't proceed because F₂ is a stronger oxidizing agent than Cl₂.

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## 🚀 BONUS: EXPLANATION OF REDOX

> Redox = Reduction + Oxidation

- Oxidation: Loss of electrons (or loss of hydrogen, or gain of oxygen)
- Reduction: Gain of electrons (or gain of hydrogen, or loss of oxygen)

In every redox reaction:
- One species is oxidized (loses e⁻)
- Another is reduced (gains e⁻)
- Electrons are transferred — not created or destroyed.

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## ✍️ FINAL ANSWERS TO FILL IN WORKSHEET:

| Overall Redox Reaction | Reduction Half-Equation |
|----------------------------------|-------------------------------|
| CuO + Mg → MgO + Cu | Cu²⁺ + 2e⁻ → Cu |
| Fe₂O₃ + 2Al → 2Fe + Al₂O₃ | Fe³⁺ + 3e⁻ → Fe |
| CuSO₄ + Zn → ZnSO₄ + Cu | Cu²⁺ + 2e⁻ → Cu |
| 2KBr + Cl₂ → 2KCl + Br₂ | Cl₂ + 2e⁻ → 2Cl⁻ |
| (Assumed) Cl₂ + 2NaF → ... | Cl₂ + 2e⁻ → 2Cl⁻ (hypothetical) |

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## 💡 TIP FOR STUDENTS:

Use the mnemonic:
> OIL RIG
> Oxidation Is Loss (of electrons)
> Reduction Is Gain (of electrons)

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✔ You’re now ready to complete your worksheet! If you want me to help with any other sections (like writing oxidation half-equations or balancing full equations), just let me know — upload more of the sheet or describe the next part.

Happy learning — and launch those rockets of knowledge! 🚀📚