Lecture Notes on Chemistry for VITEEE Preparation

Introduction

• Teacher: Dsha Koshel
• Focus: Important concepts and questions for VITEEE Chemistry preparation.

Physical Chemistry

Bohr Model

• Key concepts: radius, velocity, energy.
• n (orbit number) and Z (atomic number) are crucial.
• For first excited state: add 1 to the given orbit number.
• Radius formula: Directly proportional to n²/Z.
• Velocity: Directly proportional to Z/n.
• Energy changes and conversions.

Rydberg Equation

• Formula: ( \frac{1}{\lambda} = R_H \left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right) ).
• Series: Lyman, Balmer, Paschen - relates to UV, Visible, Infrared regions.

Quantum Numbers

• Principal (n): Size and energy.
• Azimuthal (l): Shape of orbital.
• Magnetic (ml): Orientation.
• Spin (ms): Electron rotation, ±1/2.
• Formulas: Number of subshells = n; Orbitals = n²; Electrons = 2n².

Thermodynamics

Laws and Concepts

• First Law: ( \Delta U = Q + W ).
• Processes: Isothermal, isobaric, isochoric, adiabatic.
• Heat Capacity: Important formulas involving CP and CV.
• Adiabatic Process: Temperature and work formulas.

Chemical Equilibrium

Important Concepts

• Equilibrium Constant (K): Based on product/reactant concentrations.
• Van't Hoff Equation: Relates K with temperature changes.
• Le Chatelier's Principle: Effects of pressure, temperature, concentration.

pH and Ionic Equilibrium

pH Calculations

• Strong Acids/Bases: pH calculations based on concentration.
• Buffer Solutions: Henderson-Hasselbalch equation for acidic/basic buffers.
• Salt Hydrolysis: pH of solutions with salts from strong/weak acids and bases.

Colligative Properties

Key Properties

• Relative Lowering of Vapor Pressure, Elevation in Boiling Point, Freezing Point Depression, Osmotic Pressure.
• Van't Hoff Factor (i): Indicates dissociation or association.

Chemical Kinetics

Rate Laws and Reaction Orders

• Rate Law: Based on concentration powers.
• Zero, First, Second Order Reactions: Key formulas and relations.
• Arrhenius Equation: ( k = Ae^{-\frac{E_a}{RT}} ).

Electrochemistry

Nernst Equation

• Formula: ( E = E^0 - \frac{0.059}{n} \log(Q) ).
• Gibbs Free Energy and Equilibrium: Relations between ( \Delta G, K, and E^0 ).

Solid State

Crystal Structures

• Simple, BCC, FCC: Different arrangements and calculations involving edge length and radius.
• Density formula: ( D = \frac{zM}{a^3N_A} ).

Chemical Bonding

VSEPR Theory and Shapes

• Hybridization: Determined by electron pair geometry.
• Molecular Geometry vs. Electron Geometry: Based on lone pairs.

Molecular Orbital Theory

• Bond Order: Calculated using the number of bonding and antibonding electrons.

Coordination Chemistry

VBT and CFT

• Valence Bond Theory (VBT): Hybridization and magnetic properties.
• Crystal Field Theory (CFT): Splitting of d-orbitals in different complexes.

Conclusion

• Focus on Important Topics: Bohr model, Rydberg equation, thermodynamics, chemical kinetics, and bonding theories.
• Practice with Questions: Emphasis on understanding key concepts and solving related problems.