Chemkit

Physical chemistry

Thermodynamics, kinetics, and equilibrium — gas laws, Gibbs free energy, Arrhenius kinetics, and rate-law analysis.

7 guides 3 calculators 0 cheat sheets

Reading path

Start here. Each guide is a self-contained tutorial with worked examples and cited sources.

  1. What entropy actually is Boltzmann's S = k ln W, worked out on a microstate count you can do by hand. Why 'disorder' is a lossy metaphor. 12 min
  2. Gibbs free energy in three intuitions Universe's entropy proxy, max non-PV work, distance from equilibrium — three framings of ΔG that each earn their keep. 12 min
  3. Rate laws from mechanism up Rate laws come from mechanism, not the balanced equation. Elementary steps, RDS, steady-state, integrated rate laws — and when to trust them. 13 min
  4. Transition state theory: the Eyring equation Arrhenius fits the rate; Eyring names the reason. ΔH‡ and ΔS‡ split 'why so slow' into an enthalpic hill and an entropic bottleneck. 12 min
  5. Phase diagrams: reading pressure-temperature maps One diagram encodes every phase transition a pure substance can undergo. The three lines are Clapeyron; the intersections carry the physics. 12 min
  6. The Boltzmann distribution: populations at temperature Two energy levels, one temperature — one exponential fixes the ratio. IR intensities, NMR sensitivity, and the molecular meaning of T all follow. 12 min
  7. The particle in a box: the simplest quantum problem One particle, one 1D box, one exact solution. Quantised energies, zero-point energy, and a working model for the absorption of conjugated polyenes. 12 min

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