Mnemonic 1: Molecular Speed Order — "RAM"
- R = v_Rms (largest)
- A = v_Average (middle)
- M = v_Most probable (smallest) RAM goes in descending order of speed.
Mnemonic 2: Van der Waals Constants — "a for Attraction, b for Bigness"
- a → corrects Pressure (attraction reduces wall hits)
- b → corrects Volume (bigness of molecules takes up space) High 'a' → strong attraction → easily liquefied → high T_c High 'b' → large molecules → high excluded volume
Mnemonic 3: Gas Laws — "BCA-Gay" Pattern
- Boyle = Pressure-Volume (T constant) → "Boys like Pressure"
- Charles = Volume-Temperature (P constant) → "Charles checks Temperature"
- Avogadro = Volume-Moles (T, P constant) → "Avogadro Adds molecules"
- Gay-Lussac = Pressure-Temperature (V constant) → "Gay-Lussac Gets heated in a closed container"
Mnemonic 4: Z Behavior — "Attraction Lowers, Repulsion Raises"
- Attraction → Z < 1 (gas compressed below ideal)
- Repulsion (volume) → Z > 1 (gas expands above ideal)
- , He → Always Z > 1 (no attraction, only repulsion/volume effect)
Mnemonic 5: Liquid State — "Heat Weakens Everything" At higher temperature: Viscosity decreases, Surface tension decreases, Vapour pressure increases (negative correlation only for V.P.→ wait, V.P. increases). Formula: At higher T → V.P. Up, S.T. Down, Visc. Down (U-D-D or "Up-Down-Down" starting with vapour pressure).
Mnemonic 6: Critical Constants — "8, 27, 27, 3"
- T_c = 8a/(27Rb) — numerator 8, denominator 27
- P_c = a/(27) — denominator 27
- V_c = 3b — coefficient 3