Page 1: Introduction

Chemical reaction: process where reactants converted to products with new properties.

Represented by chemical equation.

Chapter covers writing, balancing, types of reactions, corrosion, rancidity.

Page 2: Chemical Equation

Reactants → Products

Skeleton equation → not balanced

Balanced equation → atoms same on both sides (law of conservation of mass)

Page 3: Balancing Equations

Hit and trial method.

Steps: write skeleton → balance metals → non-metals → oxygen/hydrogen → check.

Page 4: Types of Reactions - Combination

Exothermic mostly.

Page 5: Decomposition

e.g., 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂ (thermal)

Page 6: Displacement

e.g., Zn + CuSO₄ → ZnSO₄ + Cu

Page 7: Double Displacement

e.g., BaCl₂ + Na₂SO₄ → BaSO₄↓ + 2NaCl

Page 8: Redox Reactions

Oxidation: loss of e⁻ / gain of O / loss of H

Reduction: gain of e⁻ / loss of O / gain of H

Displacement often redox.

Page 9: Effects of Oxidation - Corrosion

Rusting of iron: Fe + O₂ + H₂O → Fe₂O₃.xH₂O

Prevention: painting, galvanisation.

Page 10: Rancidity

Oxidation of fats/oils in food → bad smell/taste.

Prevention: antioxidants, nitrogen flushing, refrigeration.

Page 11: Key Reactions Summary

• Combination
• Decomposition (3 types)
• Displacement
• Double displacement
• Redox

Page 12: Practice Questions - Easy (1-10)

1. Balance H₂ + O₂ → H₂O.
2. Type of reaction CaO + H₂O → Ca(OH)₂.
3. Rusting prevention.
4. Rancidity meaning.
5. Displacement example.
6. Double displacement precipitate.
7. Oxidation definition.
8. Thermal decomposition example.
9. Corrosion of silver.
10. Antioxidant use.

Page 13: Practice Questions - Medium (11-20)

11. Balance Fe + H₂O → Fe₃O₄ + H₂.
12. Identify type: Zn + H₂SO₄ → ZnSO₄ + H₂.
13. Write balanced for photosynthesis.
14. Why food packets flushed with N₂.
15. Redox: CuO + H₂ → Cu + H₂O.
16. Balance Pb(NO₃)₂ decomposition.
17. Galvanisation meaning.
18. Neutralisation double displacement.
19. Identify oxidant and reductant.
20. Balance Al + HCl.

Page 14: Practice Questions - Hard (21-30)

21. Balance complex equation.
22. Identify type and balance.
23. Explain corrosion prevention methods.
24. Rancidity prevention detailed.
25. Redox identification in multiple reactions.
26. Board level balancing.
27. Write and balance respiration.
28. Real-life redox examples.
29. Multiple types in one reaction.
30. Explain law of conservation in balancing.

Page 15: Important Reactions Table

All types with examples.

Page 16: Common Mistakes

• Unbalanced equations
• Wrong reaction type
• Forgetting state symbols
• Mixing oxidation/reduction
• Wrong balancing steps

Page 17: Previous Year Questions

Balance, identify type, explain corrosion/rancidity.

Page 18: Exam Tips

• Always balance equations
• Write state symbols
• Give examples for types
• Explain prevention methods
• Show steps in balancing

Page 19: Quick Revision Sheet

All types, examples, prevention.

Page 20: Final Motivation

Chapter 1 complete! Chemical Reactions is foundation of Chemistry.

Master balancing and types.

Class 10 Science started strong 🦖

Page 21: Extra Balancing

More equations to balance.

Page 22: Reaction Types Table

With examples.

Page 23: Corrosion & Rancidity

Prevention detailed.

Page 24: Redox Identification

How to spot.

Page 25: Board Pattern

Common questions.

Page 26: Extra Practice

More questions.