Key Concepts
- Equilibrium: A state where the rate of the forward reaction is equal to the rate of the reverse reaction.
- Reversible Reaction: A reaction that can proceed in both directions under the same conditions.
- Equilibrium Constant (K): A numerical value that expresses the ratio of product concentrations to reactant concentrations at equilibrium.
- Le Châtelier's Principle: When a system at equilibrium is disturbed, it will shift in a direction to counteract the disturbance.
Factors Affecting Equilibrium
- Temperature: Increasing temperature favors the endothermic reaction.
- Pressure: Increasing pressure favors the side with fewer moles of gas.
- Concentration: Adding reactants or removing products shifts the equilibrium towards the products.
- Catalyst: A catalyst speeds up both the forward and reverse reactions equally, but it does not affect the equilibrium position.
Types of Equilibrium
- Homogeneous Equilibrium: All reactants and products are in the same phase.
- Heterogeneous Equilibrium: Reactants and products
are in different phases.
Equilibrium Expressions
- For the reaction: aA + bB ⇌ cC + dD
- Kc = [C]^c[D]^d / [A]^a[B]^b
- Kp = (PC)^c(PD)^d / (PA)^a(PB)^b
- Kc and Kp are related by the equation: Kp = Kc(RT)^(Δn), where Δn is the difference in moles of gaseous products and reactants.
Ionic Equilibrium
- Acid-Base Equilibrium:
- pH = -log[H+]
- pOH = -log[OH-]
- Kw = [H+][OH-] = 1.0 × 10^-14
- Solubility Product (Ksp): The equilibrium constant for the dissolution of a sparingly soluble salt.
- Common Ion Effect: Adding a common ion to a solution containing a sparingly soluble salt decreases its solubility.
Applications of Equilibrium
- Industrial Processes: Haber process for ammonia production, contact process for sulfuric acid production.
- Biological Systems: Enzyme-catalyzed reactions, acid-base balance in the body.
Remember: Practice solving problems to reinforce your understanding. Focus on understanding the underlying principles and applying them to different scenarios.
