CLASS 10 SCIENCE
CBSE / NCERT — Quick Revision Notes
Physics • Chemistry • Biology
Chapter-wise concepts, formulas, reactions and exam-focused points
1. Chemical Reactions and Equations
Key ideas
• A chemical reaction produces one or more new substances.
• Signs of reaction: change in colour, temperature, state, gas formation or precipitate.
Types of reactions
• Combination: A + B → AB
• Decomposition: AB → A + B (by heat, light or electricity)
• Displacement: A + BC → AC + B
• Double displacement: AB + CD → AD + CB
• Oxidation: gain of oxygen / loss of hydrogen / loss of electrons.
• Reduction: loss of oxygen / gain of hydrogen / gain of electrons.
Important equations
• 2Mg + O■ → 2MgO
• CaCO■ → CaO + CO■
• Fe + CuSO■ → FeSO■ + Cu
• AgNO■ + NaCl → AgCl↓ + NaNO■
Corrosion & rancidity
• Corrosion is slow damage of metals due to environmental reactions. Rancidity is oxidation of fats and oils. Prevention
includes painting, galvanising, refrigeration and antioxidants.
2. Acids, Bases and Salts
Key ideas
• Acids give H■ ions in aqueous solution; bases give OH■ ions.
• pH scale: 0–14. pH < 7 acidic, pH = 7 neutral, pH > 7 basic.
Reactions
• Acid + metal → salt + hydrogen
• Acid + base → salt + water (neutralisation)
• Acid + carbonate → salt + water + CO■
Important compounds
• Baking soda: NaHCO■
• Washing soda: Na■CO■·10H■O
Class 10 CBSE Science Notes • Page 1
, • Bleaching powder: CaOCl■
• Plaster of Paris: CaSO■·½H■O
Exam point
• Tooth decay begins when mouth pH falls below about 5.5.
3. Metals and Non-metals
Properties
• Metals are generally lustrous, malleable, ductile and good conductors.
• Non-metals are generally brittle and poor conductors (graphite is an important exception).
Reactivity
• K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au
• More reactive metals can displace less reactive metals from their salt solutions.
Extraction
• Highly reactive metals are obtained by electrolysis; moderately reactive metals are commonly obtained by reduction of
oxides; low-reactivity metals may be obtained by heating their ores.
Corrosion prevention
• Painting, oiling/greasing, galvanising, alloying and electroplating.
4. Carbon and Its Compounds
Core concepts
• Carbon shows tetravalency and catenation, allowing long chains and rings.
• Saturated hydrocarbons have single bonds; unsaturated hydrocarbons contain double or triple bonds.
Functional groups
• Alcohol: –OH
• Aldehyde: –CHO
• Ketone: >C=O
• Carboxylic acid: –COOH
Important reactions
• Combustion: hydrocarbon + O■ → CO■ + H■O + heat
• Ethanol + oxygen → CO■ + H■O
• Ethanoic acid + sodium hydrogen carbonate → sodium ethanoate + water + CO■
Soaps & detergents
• Soap molecules have a hydrophilic end and a hydrophobic hydrocarbon end; they form micelles around grease.
5. Life Processes
Nutrition
• Photosynthesis: 6CO■ + 6H■O → C■H■■O■ + 6O■ (in presence of light and chlorophyll).
• Human digestion involves mouth, stomach, small intestine and large intestine.
Respiration
Class 10 CBSE Science Notes • Page 2
CBSE / NCERT — Quick Revision Notes
Physics • Chemistry • Biology
Chapter-wise concepts, formulas, reactions and exam-focused points
1. Chemical Reactions and Equations
Key ideas
• A chemical reaction produces one or more new substances.
• Signs of reaction: change in colour, temperature, state, gas formation or precipitate.
Types of reactions
• Combination: A + B → AB
• Decomposition: AB → A + B (by heat, light or electricity)
• Displacement: A + BC → AC + B
• Double displacement: AB + CD → AD + CB
• Oxidation: gain of oxygen / loss of hydrogen / loss of electrons.
• Reduction: loss of oxygen / gain of hydrogen / gain of electrons.
Important equations
• 2Mg + O■ → 2MgO
• CaCO■ → CaO + CO■
• Fe + CuSO■ → FeSO■ + Cu
• AgNO■ + NaCl → AgCl↓ + NaNO■
Corrosion & rancidity
• Corrosion is slow damage of metals due to environmental reactions. Rancidity is oxidation of fats and oils. Prevention
includes painting, galvanising, refrigeration and antioxidants.
2. Acids, Bases and Salts
Key ideas
• Acids give H■ ions in aqueous solution; bases give OH■ ions.
• pH scale: 0–14. pH < 7 acidic, pH = 7 neutral, pH > 7 basic.
Reactions
• Acid + metal → salt + hydrogen
• Acid + base → salt + water (neutralisation)
• Acid + carbonate → salt + water + CO■
Important compounds
• Baking soda: NaHCO■
• Washing soda: Na■CO■·10H■O
Class 10 CBSE Science Notes • Page 1
, • Bleaching powder: CaOCl■
• Plaster of Paris: CaSO■·½H■O
Exam point
• Tooth decay begins when mouth pH falls below about 5.5.
3. Metals and Non-metals
Properties
• Metals are generally lustrous, malleable, ductile and good conductors.
• Non-metals are generally brittle and poor conductors (graphite is an important exception).
Reactivity
• K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au
• More reactive metals can displace less reactive metals from their salt solutions.
Extraction
• Highly reactive metals are obtained by electrolysis; moderately reactive metals are commonly obtained by reduction of
oxides; low-reactivity metals may be obtained by heating their ores.
Corrosion prevention
• Painting, oiling/greasing, galvanising, alloying and electroplating.
4. Carbon and Its Compounds
Core concepts
• Carbon shows tetravalency and catenation, allowing long chains and rings.
• Saturated hydrocarbons have single bonds; unsaturated hydrocarbons contain double or triple bonds.
Functional groups
• Alcohol: –OH
• Aldehyde: –CHO
• Ketone: >C=O
• Carboxylic acid: –COOH
Important reactions
• Combustion: hydrocarbon + O■ → CO■ + H■O + heat
• Ethanol + oxygen → CO■ + H■O
• Ethanoic acid + sodium hydrogen carbonate → sodium ethanoate + water + CO■
Soaps & detergents
• Soap molecules have a hydrophilic end and a hydrophobic hydrocarbon end; they form micelles around grease.
5. Life Processes
Nutrition
• Photosynthesis: 6CO■ + 6H■O → C■H■■O■ + 6O■ (in presence of light and chlorophyll).
• Human digestion involves mouth, stomach, small intestine and large intestine.
Respiration
Class 10 CBSE Science Notes • Page 2
