chemical change

 Absolutely, Mayank! Here's a concise, student-friendly summary based on the conclusion of Activities 1.1 to 1.3, which helps students clearly identify the signs of a chemical reaction. This version is perfect for note-making, classroom revision, or inclusion in a worksheet or concept chart.

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🔬 How to Identify a Chemical Reaction Has Occurred

From Activities 1.1 to 1.3, we learned that when a chemical reaction occurs, one or more of the following changes are observed:

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✅ Key Indicators of a Chemical Reaction:

1. Change in State
   ➤ Solid turns into gas, liquid turns into solid, etc.
   Example: Magnesium ribbon burns and turns to white ash (solid → new solid).

2. Change in Colour
   ➤ A new colour appears during the reaction.
   Example: Mixing lead nitrate and potassium iodide gives a yellow precipitate.

3. Evolution of a Gas
   ➤ Bubbles, fizzing, or effervescence observed.
   Example: Zinc + acid releases hydrogen gas.

4. Change in Temperature
   ➤ Heat is either released (exothermic) or absorbed (endothermic).
   Example: Zinc + HCl causes the test tube to become warm.

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📘 Conclusion:

“Whenever any of these changes occur, a chemical reaction has likely taken place. These changes help us identify when one substance is changing into another with different properties.”

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🔜 What’s Next?

Now that we know how to detect a chemical reaction, we’ll learn to:

• Represent it using chemical equations

• Classify it into types like:

  • Combination

  • Decomposition

  • Displacement

  • Double displacement

  • Redox reactions

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🧠 Quick Recall Tip:

🟡 S.C.G.T.
S – State
C – Colour
G – Gas
T – Temperature

“If you see S.C.G.T., a chemical reaction is what it must be!”

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Would you like a flowchart or flashcard design based on these indicators for class use?