1. Physisorption vs. Chemisorption Temperature Behavior:

• "Physi FEARS heat" → physisorption decreases with increasing T
• "Chemi FIRST embraces heat, then runs away" → chemisorption first increases (needs Ea), then decreases (too hot)

2. Hardy-Schulze Rule:

• "Higher Charge, Higher Power"
• Negative sol ($As_{2}S_{3}$): $Al^{3+}$ > $Ba^{2+}$ > $Na^{+}$ (cations, charge 3 > 2 > 1)
• Positive sol (Fe(OH){3}): [Fe(CN){6}]^{4-} > $PO_{4}^{3-}$ > $SO_{4}^{2-}$ > $Cl^{-}$ (anions, charge 4 > 3 > 2 > 1)

3. Gold Number:

• "Lower Gold, Greater Guard"
• Lower gold number = better protective colloid = less is needed to protect
• Ranking: Gelatin (0.005) < Albumin (0.1) < Starch (25) — in order of increasing gold number = decreasing protection

4. Colloid Particle Size:

• "1 to 1000 nm for Colloids"
• True solutions: < 1 nm (size of molecules/ions)
• Colloids: 1 nm to 1000 nm
• Suspensions: > 1000 nm (visible particles)

5. Emulsions:

• MOBY = Milk is O in W (but Y for why? because it mixes with Water)
• COBW = Cold cream, Oil continuous, Butter = W/O
• O/W (milk, vanishing cream): dilutable with WATER
• W/O (butter, cold cream): dilutable with OIL

6. Catalyst Examples:

• Haber = Fe (H and F are early letters — Haber, Fe)
• Contact = $V_{2}O_{5}$ (Contact process, Vanadium)
• Ostwald = Pt (Oxidation of NO, Platinum)

7. Lyophilic vs. Lyophobic:

• SGPG = Starch, Gelatin, Proteins, Gum arabic = Lyophilic (solvent-LOVING)
• GAF = Gold sol, As_{2}$S_{3}$ sol, Fe(OH)_{3} sol = Lyophobic (solvent-HATING)