AI Smart Notes – Class 10 Science
Chapter 1: Chemical Reactions and Equations
■ Chapter Summary:
• A chemical reaction involves change of one or more substances into new substances
with different properties.
• Indicators of a chemical reaction: color change, temperature change, gas evolution, or
precipitate formation.
• Chemical equations represent reactions using symbols and formulas. Example: 2Mg +
O■ → 2MgO.
• Balanced equations obey the Law of Conservation of Mass.
• Physical states in equations: (s) solid, (l) liquid, (g) gas, (aq) aqueous.
• Types of reactions: Combination, Decomposition, Displacement, Double Displacement,
Oxidation-Reduction.
• Combination reaction: CaO + H■O → Ca(OH)■ (Exothermic).
• Decomposition reaction: CaCO■ → CaO + CO■ (Thermal).
• Displacement reaction: Fe + CuSO■ → FeSO■ + Cu.
• Double displacement: Na■SO■ + BaCl■ → BaSO■ + 2NaCl.
• Oxidation = gain of oxygen/loss of hydrogen. Reduction = loss of oxygen/gain of
hydrogen.
• Corrosion is the gradual destruction of metals due to moisture and oxygen. Rusting is an
example.
• Rancidity occurs when oils/fats oxidize; prevent by airtight storage or nitrogen flushing.
■ 20 Multiple Choice Questions
No Question Answer
1 Which observation does not indicate a chemical reaction? Melting of ice
2 Law of Conservation of Mass was given by: Lavoisier
3 Arrow in a chemical equation indicates: Direction of reaction
4 Example of combination reaction: CaO + H■O → Ca(OH)■
5 Example of thermal decomposition: CaCO■ → CaO + CO■
6 Reaction requiring light energy: 2AgCl → 2Ag + Cl■
7 Example of displacement reaction: Zn + CuSO■ → ZnSO■ + Cu
8 Exchange of ions occurs in: Na■SO■ + BaCl■ → BaSO■ + 2NaCl
9 Oxidation means: Gain of oxygen
10 Reduction means: Loss of oxygen
11 Both oxidation & reduction occur in: Redox reaction
12 Example of redox reaction: CuO + H■ → Cu + H■O
13 Rusting is caused by: Oxidation of iron
14 Rancidity occurs due to: Oxidation of oils/fats
15 Endothermic reaction absorbs: Energy
16 Exothermic example: CH■ + 2O■ → CO■ + 2H■O
Chapter 1: Chemical Reactions and Equations
■ Chapter Summary:
• A chemical reaction involves change of one or more substances into new substances
with different properties.
• Indicators of a chemical reaction: color change, temperature change, gas evolution, or
precipitate formation.
• Chemical equations represent reactions using symbols and formulas. Example: 2Mg +
O■ → 2MgO.
• Balanced equations obey the Law of Conservation of Mass.
• Physical states in equations: (s) solid, (l) liquid, (g) gas, (aq) aqueous.
• Types of reactions: Combination, Decomposition, Displacement, Double Displacement,
Oxidation-Reduction.
• Combination reaction: CaO + H■O → Ca(OH)■ (Exothermic).
• Decomposition reaction: CaCO■ → CaO + CO■ (Thermal).
• Displacement reaction: Fe + CuSO■ → FeSO■ + Cu.
• Double displacement: Na■SO■ + BaCl■ → BaSO■ + 2NaCl.
• Oxidation = gain of oxygen/loss of hydrogen. Reduction = loss of oxygen/gain of
hydrogen.
• Corrosion is the gradual destruction of metals due to moisture and oxygen. Rusting is an
example.
• Rancidity occurs when oils/fats oxidize; prevent by airtight storage or nitrogen flushing.
■ 20 Multiple Choice Questions
No Question Answer
1 Which observation does not indicate a chemical reaction? Melting of ice
2 Law of Conservation of Mass was given by: Lavoisier
3 Arrow in a chemical equation indicates: Direction of reaction
4 Example of combination reaction: CaO + H■O → Ca(OH)■
5 Example of thermal decomposition: CaCO■ → CaO + CO■
6 Reaction requiring light energy: 2AgCl → 2Ag + Cl■
7 Example of displacement reaction: Zn + CuSO■ → ZnSO■ + Cu
8 Exchange of ions occurs in: Na■SO■ + BaCl■ → BaSO■ + 2NaCl
9 Oxidation means: Gain of oxygen
10 Reduction means: Loss of oxygen
11 Both oxidation & reduction occur in: Redox reaction
12 Example of redox reaction: CuO + H■ → Cu + H■O
13 Rusting is caused by: Oxidation of iron
14 Rancidity occurs due to: Oxidation of oils/fats
15 Endothermic reaction absorbs: Energy
16 Exothermic example: CH■ + 2O■ → CO■ + 2H■O
