Class 10 Chemistry – Chapter 1
Chemical Equilibrium
Definition
Chemical equilibrium is a state in a reversible reaction where the rate of forward reaction equals
the rate of backward reaction and the concentrations of reactants and products remain constant.
Types of Reactions
1. Irreversible Reactions – Reactions that proceed in one direction only.
Example:
C+O2→CO2C + O_2 \rightarrow CO_2C+O2→CO2
2. Reversible Reactions – Reactions that can proceed in both forward and backward
directions.
Example:
N2+3H2⇌2NH3N_2 + 3H_2 \rightleftharpoons 2NH_3N2+3H2⇌2NH3
Characteristics of Chemical Equilibrium
It is dynamic in nature (both reactions occur simultaneously).
Concentrations of reactants and products remain constant.
Can be attained only in closed systems.
Forward and backward rates are equal at equilibrium.
Law of Mass Action
Definition:
The rate of a chemical reaction is directly proportional to the product of the molar concentrations
of reactants, each raised to a power equal to its stoichiometric coefficient.
Mathematical Form:
,k=[Products][Reactants]k = \frac{[Products]}{[Reactants]}k=[Reactants][Products]
Equilibrium Constant (Kc)
Kc=[C]c[D]d[A]a[B]bK_c = \frac{[C]^c [D]^d}{[A]^a [B]^b}Kc=[A]a[B]b[C]c[D]d
Large KcK_cKc → Products favored.
Small KcK_cKc → Reactants favored.
Factors Affecting Equilibrium (Le Chatelier’s Principle)
1. Concentration – Increasing concentration of reactants shifts equilibrium to products.
2. Temperature –
o Endothermic: Increase T → products.
o Exothermic: Increase T → reactants.
3. Pressure – Higher pressure favors fewer moles of gas.
4. Catalyst – Speeds up both reactions equally, no change in equilibrium position.
Examples
1. Haber Process
N2+3H2⇌2NH3N_2 + 3H_2 \rightleftharpoons 2NH_3N2+3H2⇌2NH3
Conditions: High pressure, moderate temperature, iron catalyst.
2. Contact Process
2SO2+O2⇌2SO32SO_2 + O_2 \rightleftharpoons 2SO_32SO2+O2⇌2SO3
Catalyst: Vanadium pentoxide.
Quick Summary Table:
Factor Effect on Equilibrium
↑ Reactants Shift → Products
↑ Temperature (Endothermic) Products
↑ Pressure (less gas moles) Favors fewer moles
, Factor Effect on Equilibrium
Catalyst No position change
Class 10 Chemistry Notes
Chapter 2 – Atomic Structure
1. Introduction
Matter is made up of atoms.
The structure of an atom helps to explain its properties and behavior.
This chapter discusses atomic models, subatomic particles, and electron arrangement.
2. Subatomic Particles
Particle Symbol Charge Relative Mass Location in Atom
Proton p⁺ +1 1 amu Nucleus
Neutron n⁰ 0 1 amu Nucleus
Electron e⁻ -1 1/1836 amu Electron shells
3. Atomic Models
a. Dalton’s Atomic Theory
All matter is made of indivisible atoms.
Atoms of same element are identical.
Atoms combine in whole number ratios to form compounds.
b. Thomson’s Plum Pudding Model
Atom is a positively charged sphere with electrons embedded.
Chemical Equilibrium
Definition
Chemical equilibrium is a state in a reversible reaction where the rate of forward reaction equals
the rate of backward reaction and the concentrations of reactants and products remain constant.
Types of Reactions
1. Irreversible Reactions – Reactions that proceed in one direction only.
Example:
C+O2→CO2C + O_2 \rightarrow CO_2C+O2→CO2
2. Reversible Reactions – Reactions that can proceed in both forward and backward
directions.
Example:
N2+3H2⇌2NH3N_2 + 3H_2 \rightleftharpoons 2NH_3N2+3H2⇌2NH3
Characteristics of Chemical Equilibrium
It is dynamic in nature (both reactions occur simultaneously).
Concentrations of reactants and products remain constant.
Can be attained only in closed systems.
Forward and backward rates are equal at equilibrium.
Law of Mass Action
Definition:
The rate of a chemical reaction is directly proportional to the product of the molar concentrations
of reactants, each raised to a power equal to its stoichiometric coefficient.
Mathematical Form:
,k=[Products][Reactants]k = \frac{[Products]}{[Reactants]}k=[Reactants][Products]
Equilibrium Constant (Kc)
Kc=[C]c[D]d[A]a[B]bK_c = \frac{[C]^c [D]^d}{[A]^a [B]^b}Kc=[A]a[B]b[C]c[D]d
Large KcK_cKc → Products favored.
Small KcK_cKc → Reactants favored.
Factors Affecting Equilibrium (Le Chatelier’s Principle)
1. Concentration – Increasing concentration of reactants shifts equilibrium to products.
2. Temperature –
o Endothermic: Increase T → products.
o Exothermic: Increase T → reactants.
3. Pressure – Higher pressure favors fewer moles of gas.
4. Catalyst – Speeds up both reactions equally, no change in equilibrium position.
Examples
1. Haber Process
N2+3H2⇌2NH3N_2 + 3H_2 \rightleftharpoons 2NH_3N2+3H2⇌2NH3
Conditions: High pressure, moderate temperature, iron catalyst.
2. Contact Process
2SO2+O2⇌2SO32SO_2 + O_2 \rightleftharpoons 2SO_32SO2+O2⇌2SO3
Catalyst: Vanadium pentoxide.
Quick Summary Table:
Factor Effect on Equilibrium
↑ Reactants Shift → Products
↑ Temperature (Endothermic) Products
↑ Pressure (less gas moles) Favors fewer moles
, Factor Effect on Equilibrium
Catalyst No position change
Class 10 Chemistry Notes
Chapter 2 – Atomic Structure
1. Introduction
Matter is made up of atoms.
The structure of an atom helps to explain its properties and behavior.
This chapter discusses atomic models, subatomic particles, and electron arrangement.
2. Subatomic Particles
Particle Symbol Charge Relative Mass Location in Atom
Proton p⁺ +1 1 amu Nucleus
Neutron n⁰ 0 1 amu Nucleus
Electron e⁻ -1 1/1836 amu Electron shells
3. Atomic Models
a. Dalton’s Atomic Theory
All matter is made of indivisible atoms.
Atoms of same element are identical.
Atoms combine in whole number ratios to form compounds.
b. Thomson’s Plum Pudding Model
Atom is a positively charged sphere with electrons embedded.
