Chemical Equilibrium
Chemical equilibrium occurs when forward and reverse reaction rates are equal. Master Le Chatelier's principle, equilibrium constants (Kc, Kp), ICE tables, and how to predict equilibrium shifts.
Key Concepts
Study Tips
- ✓Pure solids and liquids are NOT included in equilibrium expressions
- ✓Kp = Kc(RT)^(delta n) where delta n = moles gas products - moles gas reactants
- ✓Compare Q to K to predict which direction the reaction will shift
- ✓Le Chatelier's principle: systems shift to counteract applied stress
Common Mistakes to Avoid
Students often include pure solids/liquids in K expressions, confuse Q and K, forget that catalysts don't affect equilibrium position (only rate), and misapply Le Chatelier's principle. Remember: adding an inert gas at constant volume doesn't shift equilibrium.
Chemical Equilibrium FAQs
Common questions about chemical equilibrium
K is the equilibrium constant at a specific temperature - it's a fixed value. Q is the reaction quotient calculated from current concentrations, which may not be at equilibrium. If Q < K, reaction goes forward. If Q > K, reaction goes backward. If Q = K, system is at equilibrium.
ICE stands for Initial, Change, Equilibrium. Write initial concentrations, then express changes in terms of x using stoichiometry. Equilibrium = Initial + Change. Substitute into K expression and solve for x.
No! Catalysts speed up both forward and reverse reactions equally, so equilibrium is reached faster but the final position (K value) doesn't change. Catalysts lower activation energy but don't change thermodynamics.