Class notes Chemistry

This is basically your Thermodynamics long notes—it explains how energy, heat, and work behave in systems (like gases, liquids, etc.). Think of it as answering 3 big questions: Can a reaction happen? (Thermodynamics) How far will it go? (Equilibrium) How fast will it happen? (Kinetics) 1. System & Surroundings System → The part you are studying (like gas in a container) Surroundings → Everything else outside Universe = System + Surroundings Example: Water in a beaker = system, air outside = surroundings 2. Boundary Boundary is just the separator between system & surroundings. Types: Real / Imaginary Rigid → Volume fixed Non-rigid → Volume changes Diathermic → Heat can pass Adiabatic → No heat exchange 3. Types of Systems Open system → Exchanges mass & energy Closed system → Only energy exchange Isolated system → No exchange at all 4. Properties Extensive (depend on size) Mass, volume, heat capacity Change when system is divided Intensive (independent of size) Temperature, pressure, density Stay same even if divided 5. State vs Path Function State function → Depends only on initial & final state (U, H, S, G) Path function → Depends on how you reach there (Heat q, Work W) Like: Height of mountain = state Path you took = path function 6. Thermodynamic Processes Different ways system can change: Isothermal → Temperature constant Isobaric → Pressure constant Isochoric → Volume constant Adiabatic → No heat exchange Cyclic → Returns to initial state 7. Thermodynamic Equilibrium System is stable when: Thermal equilibrium → Temp constant Mechanical equilibrium → No pressure imbalance Chemical equilibrium → Concentration constant 8. Reversible vs Irreversible Reversible: Happens very slowly Equilibrium at every step Can be reversed Irreversible: Happens fast Only initial & final equilibrium Cannot be reversed 9. Heat & Work Heat = energy in transfer Units → Joule (J) Sign convention: Heat absorbed = +ve Heat released = -ve 10. Internal Energy (U) Total energy inside system Includes kinetic + potential + molecular energy For ideal gas: 11. Heat Capacity Heat required to raise temperature Types: Molar heat capacity (Cm) → per mole Specific heat capacity (Cs) → per gram