physical

## What I do - Explain physical chemistry principles - Describe thermodynamic concepts - Discuss quantum mechanics basics - Analyze molecular behavior - Explain chemical kinetics - Connect theory to observation ## When to use me - When learning physical chemistry basics - When explaining thermodynamic principles - When studying quantum chemistry - When preparing educational content ## Key Concepts ### Thermodynamics **State Functions** - Internal energy (U) - Enthalpy (H) - Entropy (S) - Gibbs free energy (G) **First Law**: ΔU = q + w **Second Law**: ΔS_universe ≥ 0 **Third Law**: S → 0 as T → 0 ### Quantum Mechanics ```python # Schrödinger equation (time-independent) # HΨ = EΨ # Particle in a box (1D) def particle_in_box_energy(n, m, L): """ Calculate energy levels. n: quantum number (1, 2, 3, ...) m: particle mass L: box length """ h = 6.626e-34 # Planck constant return (n**2 * h**2) / (8 * m * L**2) # Heisenberg uncertainty # Δx · Δp ≥ ℏ/2 ``` ### Kinetics - Rate = k[A]ⁿ[B]ᵐ - Arrhenius: k = A·e^(-Ea/RT) - Half-life equations - Reaction coordinate diagrams - Catalysts lower activation energy ### States of Matter - **Solids**: Fixed shape/volume, ordered - **Liquids**: Fixed volume, variable shape - **Gases**: Variable volume/shape, disordered - **Plasma**: Ionized gas (high energy) - **Bose-Einstein condensate**: Supercooled atoms