Introduction -1

1. 🎤 Start with Daily Life Examples (5 mins)

Engage students by asking:

“What happens when milk turns sour? Or when iron rusts? Or when we cook food?”

Let them respond, then say:

✅ “All these are chemical reactions — new substances are formed with new properties.”

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2. 🔍 Definition of a Chemical Reaction (Board Explanation)

📘 Definition:

A chemical reaction is a process in which one or more reactants are converted into one or more products with new properties.

✅ Emphasize: It's not just a change in form or appearance — it's a new substance being formed.

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3. 🧪 Show a Simple Activity/Demo

Activity: Burning Magnesium Ribbon

• Clean a small strip of magnesium ribbon.

• Hold it with tongs and burn it in a flame.

• Ask students to observe:

  • Bright white light

  • White ash (magnesium oxide) is formed.

✅ Reaction:

$$\text{Mg (s)} + \text{O}_2 (g) \rightarrow \text{MgO (s)}$$

🧠 Ask: “Is this a new substance? Did something new form?”
→ Reinforce the idea of a chemical reaction.

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4. ✅ Characteristics of Chemical Reactions

List and explain five key signs of a chemical reaction:

Characteristic	Example
Change in state	Water → steam during electrolysis
Change in colour	Copper sulphate + iron → greenish solution
Gas is evolved	Zinc + HCl → Hydrogen gas
Change in temperature	CaO + H₂O → heat released
Formation of precipitate	BaCl₂ + Na₂SO₄ → white ppt of BaSO₄

👀 Use simple demonstrations or videos for each.

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5. 🔁 Differentiate Physical vs Chemical Change

Give a comparison chart:

Physical Change	Chemical Change
No new substance formed	New substance formed
Often reversible	Usually irreversible
Example: Melting ice	Example: Rusting of iron

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6. 🧠 Ask Students to Identify Reactions

Show or describe scenarios. Ask:
“Is this a chemical reaction? Why?”

Examples:

• Melting of butter → Physical

• Cooking an egg → Chemical

• Burning wood → Chemical

• Dissolving salt in water → Physical

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7. 📘 Introduce the Term "Chemical Equation"

Tease what’s coming next:

“Now that we know what a chemical reaction is, how do we represent it in a scientific way? That’s what we’ll learn next — chemical equations!”

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✅ Key Teaching Aids You Can Use

• Real-life examples

• Classroom demonstrations

• Flashcards or pictorial prompts

• A short quiz or match-the-following

• Hand-drawn mind map of reaction characteristics

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📝 Quick Homework / Practice Suggestion

Ask students to:

• List 3 chemical reactions from their home or surroundings.

• Write what change was observed and what new substance was formed.

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🎤 Closing Line for Class:

“Chemical reactions are happening all around you — in your kitchen, your breath, even in your stomach. All of chemistry starts from recognizing these changes!”

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Would you like a visual flowchart or class slide deck for this introduction?