NCERT Class 10 Science – Chapter 1: Chemical
Reactions & Equations
1. Introduction
● A chemical reaction is a process in which one or more substances (reactants)
undergo a chemical change to form new substances (products).
● It is represented by a chemical equation, which shows the reactants and products
along with their physical states.
2. Chemical Equations
● Example:
● Balanced Equation: The number of atoms of each element must be the same on
both sides of the equation.
● Steps to Balance:
1. Write the unbalanced equation.
2. Count the number of atoms of each element.
3. Adjust coefficients to balance the atoms.
4. Verify the equation.
3. Types of Chemical Reactions
A. Combination Reaction
● A reaction in which two or more reactants combine to form a single product.
● Example:
B. Decomposition Reaction
● A reaction where a single compound breaks down into two or more simpler
substances.
Reactions & Equations
1. Introduction
● A chemical reaction is a process in which one or more substances (reactants)
undergo a chemical change to form new substances (products).
● It is represented by a chemical equation, which shows the reactants and products
along with their physical states.
2. Chemical Equations
● Example:
● Balanced Equation: The number of atoms of each element must be the same on
both sides of the equation.
● Steps to Balance:
1. Write the unbalanced equation.
2. Count the number of atoms of each element.
3. Adjust coefficients to balance the atoms.
4. Verify the equation.
3. Types of Chemical Reactions
A. Combination Reaction
● A reaction in which two or more reactants combine to form a single product.
● Example:
B. Decomposition Reaction
● A reaction where a single compound breaks down into two or more simpler
substances.
