Class 10 Science Notes Chapter 1: Chemical Reactions and
Equations
These notes are specially designed for CBSE Class 10 students. They include all important concepts, definitions,
examples, equations, NCERT points, and exam-ready explanations from Chapter 1.
1. Chemical Reaction
A process in which one or more substances react to form new substances with different properties.
Examples:
• Burning of magnesium ribbon
• Rusting of iron
• Digestion of food
2. Characteristics of Chemical Reactions
Signs that a chemical reaction has taken place:
• Change in colour
• Change in temperature
• Evolution of gas
• Formation of precipitate
• Change in state
3. Chemical Equations
A chemical equation represents a chemical reaction using symbols and formulae.
Example:
Magnesium + Oxygen → Magnesium Oxide
2Mg + O■ → 2MgO
4. Balanced Chemical Equation
A balanced chemical equation has an equal number of atoms of each element on both sides.
Law of Conservation of Mass:
Mass can neither be created nor destroyed in a chemical reaction.
5. Types of Chemical Reactions
A. Combination Reaction:
Two or more substances combine to form a single product.
Equations
These notes are specially designed for CBSE Class 10 students. They include all important concepts, definitions,
examples, equations, NCERT points, and exam-ready explanations from Chapter 1.
1. Chemical Reaction
A process in which one or more substances react to form new substances with different properties.
Examples:
• Burning of magnesium ribbon
• Rusting of iron
• Digestion of food
2. Characteristics of Chemical Reactions
Signs that a chemical reaction has taken place:
• Change in colour
• Change in temperature
• Evolution of gas
• Formation of precipitate
• Change in state
3. Chemical Equations
A chemical equation represents a chemical reaction using symbols and formulae.
Example:
Magnesium + Oxygen → Magnesium Oxide
2Mg + O■ → 2MgO
4. Balanced Chemical Equation
A balanced chemical equation has an equal number of atoms of each element on both sides.
Law of Conservation of Mass:
Mass can neither be created nor destroyed in a chemical reaction.
5. Types of Chemical Reactions
A. Combination Reaction:
Two or more substances combine to form a single product.
