Chemical Reactions & Equations Revision Class 10 Science
Pandey Sir’s BEST Classes — One-Page Revision
Chemical Reactions and Equations — Class 10 Science Ch1 Revision
CBSE 2026–27 · NCERT-aligned · Print + revise — scoped fragment (H2-first)
PAGE TITLE: Chemical Reactions and Equations Revision Sheet Class 10 Science | Pandey Sir BEST Classes — keyword: `class 10 science chemical reactions revision sheet`
🎯 Outcomes
- Write & balance equations (hit-and-trial)
- Classify: combination/decomposition/displacement/double/precipitate
- Identify redox: oxidation = gain O / loss H
- Explain corrosion vs rancidity + prevention
🧠 Memory Hooks
- Balance: “Atoms in = atoms out” — never change subscript.
- Types: C D D D P → “Cat Did Double Precipitate”.
- Redox: OIL RIG? Oxidation Is Loss (e-), here via O/H.
- Rancidity: Nitrogen bag → no O2 → no foul smell.
⚡ Vault — Key Equations to Memorize
Combination
2Mg + O2 → 2MgO | CaO + H2O → Ca(OH)2 + heat
Decomposition (3 energies)
Thermal: CaCO3 → CaO + CO2 | Photo: 2AgCl → 2Ag + Cl2 | Electro: 2H2O → 2H2 + O2
Displacement / Double
Fe + CuSO4 → FeSO4 + Cu | BaCl2 + Na2SO4 → BaSO4↓ + 2NaCl (white)
Redox Example
CuO + H2 → Cu + H2O (CuO reduced, H2 oxidised)
📋 Reaction Types — Quick Table
| Type | Form | Board Eg. |
|---|---|---|
| Combination | A+B→AB | Burning Mg |
| Decomposition | AB→A+B | Pb(NO3)2 → PbO+NO2 |
| Displacement | A+BC→AC+B | Fe+CuSO4 |
| Double | AB+CD→AD+CB | BaCl2+Na2SO4 |
| Precipitate | solid ↓ | BaSO4 white, PbI2 yellow |
⚠️ Common Traps
| Trap | Fix |
|---|---|
| Change subscript to balance | Change coefficients only |
| Precipitate = combination | It is double displacement |
| Corrosion = rancidity | Metals rust vs fats oxidise |
| Photo vs thermal same | AgCl needs light, CaCO3 needs heat |
Topper Tip: Always mark gas ↑ and precipitate ↓ in equation — board awards marks.
🔁 2-3-5-7 Plan — Chemical Reactions
Day 2
Rebalance 5 equations timed
Rebalance 5 equations timed
Day 3
Classify 10 reactions by type
Classify 10 reactions by type
Day 5
10 MCQs (Section A) in 12 min
10 MCQs (Section A) in 12 min
Day 7
One CBQ + redox label
One CBQ + redox label
📊 Self-Check (tap to reveal)
Q: Balance Fe + H2O → Fe3O4 + H2
3Fe + 4H2O → Fe3O4 + 4H2
Q: Fe+CuSO4 → ? Type?
FeSO4 + Cu — displacement, Fe more reactive.
Q: Prevent rancidity 4 ways?
Antioxidant, air-tight, nitrogen flush, refrigeration.
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