• Surface chemistry

• Surface

• Catalysis

• Colloids

• Decrease size of particles the surface area increases

• Percentage of surface molecules as particles size decreases

• Absorption

• S\G interface

• Denotion of $\frac{x}{m}$

• $\frac{x}{m}$ = $\frac{Mass \hspace{1mm} of\hspace{1mm} gas \hspace{1mm}adsorbed}{Mass \hspace{1mm}of \hspace{1mm}solid}$

Example - Argon on coconut charcoal at $-78.3^oC$

• Example - Adsorption of acetone in water on “blood charcoal” $T=18^oC$

• K and $\frac{1}{n}$ Depends on adsorbate , adsorbent , temperature

• log $(\frac{x}{m})$= log a = logk+$(\frac{1}{n})log (\frac{p}{c})$

• y = C+mx

• Le chatelier principle

• Physisorption

• Chemisorption

• Diatomic molecule potential energy on a function of distance from the surface

• $N_2 + 3H_2$ $\rightarrow$ $2NH_3$

• Physisorption

• Non selective

• $\Delta$ $H_{ad}$ ~ 10-40 kJ/mol (condensation)

• Reversible

• Intermolecular forces

• Instantaneous

• No activation energy

• Chemisorption

  • Selective

  • Irreversible

  • $\Delta$ $H_{ad}$ ~ 100-250 kJ/mol

  • Chemical bond

  • Finite time

  • Activated adsorption

• $H_2(s)$ $\rightarrow$ $2H(g)$

• $\Delta H$ $\uparrow$

• $H_g(g) \rightarrow$ PE Surface -H(s) $\Delta H$