Comprehensive notes on Chemical Equilibrium, Reversible Reactions, Law of Mass Action, Kc, Kp, Le Chatelier's Principle, and Industrial Applications (Haber's & Contact Process).
Reversible Reactions: Reactions which proceed in both forward and reverse directions. Represented by double arrow (↔).
Dynamic Equilibrium: The state where the rate of forward reaction equals the rate of reverse reaction. Net change in concentration is zero, though molecules are constantly reacting.
Law: Rate is directly proportional to the product of active masses of reactants.
Expression: For aA + bB ↔ cC + dD, Kc = [C]c[D]d / [A]a[B]b.
Units: Depends on Δn. If Δn=0, no units.
Kp = Kc(RT)Δn.
If Δn > 0 (more product moles), Kp > Kc.
If Δn < 0 (less product moles), Kp < Kc.
If Δn = 0, Kp = Kc.
If a stress (change in Conc, Pressure, Temp) is applied to a system at equilibrium, the system acts to relieve that stress.
1. Concentration: Adding reactant shifts right. Removing product shifts right.
2. Pressure: Increasing pressure shifts towards side with fewer gaseous moles.
3. Temperature:
- Exothermic: Increase T shifts left (Kc decreases).
- Endothermic: Increase T shifts right (Kc increases).
Haber's Process (NH3): N2 + 3H2 ↔ 2NH3 (ΔH = -92 kJ).
Conditions: High P (200 atm), Low T (450°C optimized), Fe catalyst.
Contact Process (SO3): 2SO2 + O2 ↔ 2SO3 (ΔH = -196 kJ).
Conditions: High P (1 atm is sufficient), Low T (450°C), V2O5 catalyst.
Product of molar concentrations of ions in a saturated solution. For AgCl ↔ Ag+ + Cl-, Ksp = [Ag+][Cl-].
If Ionic Product < Ksp → Unsaturated.
If Ionic Product > Ksp → Precipitation occurs.
Suppression of ionization of a weak electrolyte by adding a strong electrolyte containing a common ion. Used in salt analysis (Group II & IV) and purification of NaCl.