IOE Entrance notes
IoeChemistry•Updated: 5/8/2026
📘 CHEMISTRY NOTES
1. PHYSICAL CHEMISTRY
1.1 CHEMICAL ARITHMETIC
Dalton’s Atomic Theory
Dalton’s atomic theory states that matter is composed of tiny indivisible particles called atoms.
Main Postulates
• Atoms cannot be created or destroyed • Atoms of the same element are identical • Different elements have different atoms • Chemical reactions involve rearrangement of atoms
Laws of Stoichiometry
Law of Conservation of Mass
Mass can neither be created nor destroyed.
Law of Constant Proportion
A compound always contains elements in fixed proportion.
Atomic Mass and Molecular Mass
Atomic Mass
Mass of one atom relative to carbon-12.
Molecular Mass
Sum of atomic masses of all atoms in a molecule.
Example:
$$ H_2O = 2(1) + 16 = 18 $$
Empirical Formula
Simplest whole number ratio of atoms in a compound.
Molecular Formula
Actual number of atoms in a molecule.
Limiting Reagent
The reactant consumed first during a chemical reaction.
Avogadro Hypothesis
Equal volumes of gases contain equal number of molecules at same temperature and pressure.
Avogadro Number
$$ N_A = 6.022 \times 10^{23} $$
Equivalent Mass
Mass of substance that combines with one part by mass of hydrogen.
1.2 STATE OF MATTER
Gaseous State
Gas particles move freely and occupy entire volume.
Ideal Gas Equation
$$ PV = nRT $$
Liquid State
Liquids have definite volume but no definite shape.
Solid State
Solids have fixed shape and fixed volume.
Types
• Crystalline Solid • Amorphous Solid
1.3 ATOMIC STRUCTURE AND PERIODIC CLASSIFICATION
Atomic Structure
Atom consists of electrons, protons and neutrons.
Bohr’s Model
Electrons revolve in fixed energy levels.
Quantum Numbers
• Principal Quantum Number • Azimuthal Quantum Number • Magnetic Quantum Number • Spin Quantum Number
Periodic Classification
Elements are arranged according to atomic number.
Periodic Properties
• Atomic Radius • Ionization Energy • Electron Affinity • Electronegativity
1.4 OXIDATION, REDUCTION AND EQUILIBRIUM
Oxidation
Addition of oxygen or removal of hydrogen.
Reduction
Removal of oxygen or addition of hydrogen.
Redox Reaction
Reaction involving oxidation and reduction simultaneously.
Chemical Equilibrium
Rate of forward and backward reactions become equal.
Equilibrium Constant
$$ K_c = \frac{ [Products] }{ [Reactants] } $$
1.5 VOLUMETRIC ANALYSIS
Volumetric analysis determines concentration using titration.
Types of Titration
• Acid-Base Titration • Redox Titration • Precipitation Titration
Neutralization Formula
$$ N_1V_1 = N_2V_2 $$
1.6 IONIC EQUILIBRIUM, ACID, BASE AND SALT
Acid
Produces (H^+) ions in solution.
Base
Produces (OH^-) ions in solution.
Salt
Formed from acid-base reaction.
pH Scale
$$ pH = -\log[H^+] $$
Ionic Equilibrium
Equilibrium involving ions in solution.
1.7 ELECTROCHEMISTRY
Electrochemistry studies conversion between chemical and electrical energy.
Electrolyte
Substance conducting electricity in solution.
Faraday’s Law
Mass deposited is proportional to charge passed.
Cell Potential
$$ E_{cell}
E_{cathode}
E_{anode} $$
1.8 ENERGETICS, KINETICS AND CHEMICAL BONDING
Energetics of Chemical Reaction
Study of heat changes during reaction.
Enthalpy Change
$$ \Delta H = H_p - H_r $$
Chemical Kinetics
Study of reaction rate.
Rate Law
$$ Rate = k[A]^m[B]^n $$
Chemical Bonding
Attractive force holding atoms together.
Types
• Ionic Bond • Covalent Bond • Coordinate Bond • Metallic Bond
Shape of Molecules
Determined using VSEPR theory.
Examples:
• Linear • Bent • Tetrahedral • Trigonal Planar
2. INORGANIC CHEMISTRY
2.1 NON-METALS
Hydrogen
Lightest element with atomic number 1.
Oxygen
Supports combustion and respiration.
Ozone
Triatomic form of oxygen.
Formula
$$ O_3 $$
Water
Universal solvent essential for life.
Nitrogen and its Compounds
Important compounds:
• Ammonia • Nitric Acid • Nitrogen Oxides
Halogens
Highly reactive non-metals.
Elements
• Fluorine • Chlorine • Bromine • Iodine
Carbon
Exists in allotropes:
• Diamond • Graphite • Fullerene
Phosphorus and Sulphur
Important industrial non-metals.
Noble Gases
Chemically inert gases.
Examples
• Helium • Neon • Argon
Environmental Pollution
Types:
• Air Pollution • Water Pollution • Soil Pollution
2.2 METALS
Metallurgical Principle
Extraction of metals from ores.
Alkali Metals
Highly reactive Group 1 elements.
Alkaline Earth Metals
Group 2 elements.
Coinage Metals
• Copper • Silver • Gold
2.3 EXTRACTION OF METALS
Extraction of Zinc
Obtained from zinc blende.
Extraction of Mercury
Obtained from cinnabar ore.
Iron Compounds
Important compounds:
• Ferrous Sulphate • Ferric Chloride
3. ORGANIC CHEMISTRY
3.1 INTRODUCTION
Organic chemistry studies carbon compounds.
Purification of Organic Compounds
Methods:
• Distillation • Sublimation • Crystallization
Nomenclature of Organic Compounds
Naming based on IUPAC system.
Isomerism
Compounds with same formula but different structure.
Reaction Mechanism
Stepwise pathway of reaction.
3.2 HYDROCARBONS
Alkanes
Saturated hydrocarbons.
General Formula
$$ C_nH_{2n+2} $$
Alkenes
Contain double bond.
General Formula
$$ C_nH_{2n} $$
Alkynes
Contain triple bond.
General Formula
$$ C_nH_{2n-2} $$
Aromatic Hydrocarbons
Contain benzene ring.
Example:
$$ C_6H_6 $$
3.3 HALOALKANES AND HALOARENES
Organic compounds containing halogens.
Examples:
• Chloroform • Chlorobenzene
3.4 ALCOHOLS, PHENOLS AND ETHERS
Alcohol
Contains (OH) group.
Example:
$$ C_2H_5OH $$
Phenol
Hydroxyl group attached to benzene ring.
Ether
Contains oxygen atom between two alkyl groups.
3.5 ALDEHYDES, KETONES AND CARBOXYLIC ACIDS
Aldehyde
Contains (CHO) group.
Ketone
Contains carbonyl group between carbons.
Carboxylic Acid
Contains (COOH) group.
3.6 NITRO COMPOUNDS AND AMINES
Nitro Compounds
Contain nitro group (NO_2).
Amines
Derived from ammonia.
Types
• Primary Amine • Secondary Amine • Tertiary Amine
EXAM TIPS
• Learn reactions regularly • Practice numerical problems • Memorize important formulas • Focus on organic mechanisms • Revise periodic trends daily
QUICK REVISION FORMULAS
Topic | Formula |
|---|---|
Ideal Gas Equation | $$PV = nRT$$ |
pH Formula | $$pH=-\log[H^+]$$ |
Neutralization | $$N_1V_1=N_2V_2$$ |
Alkane Formula | $$C_nH_{2n+2}$$ |
Alkene Formula | $$C_nH_{2n}$$ |
Alkyne Formula | $$C_nH_{2n-2}$$ |
Avogadro Number | $$6.022\times10^{23}$$ |