Chemical Equilibrium and Le Chatelier’s Principle

🟢 Lite — Quick Review (1h–1d)

Rapid summary for last-minute revision before your exam.

Chemical Equilibrium and Le Chatelier’s Principle — Key Facts for NECO Definition: At equilibrium, forward reaction rate = backward reaction rate; concentrations stay constant (not equal) Le Chatelier’s Principle: System responds to oppose any change imposed on it Kc and Kp: Equilibrium constants — larger K means products favored; smaller K means reactants favored ⚡ Exam tip: Changing concentration, temperature, pressure, or adding a catalyst shifts equilibrium — know which direction and why

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🟡 Standard — Regular Study (2d–2mo)

Standard content for students with a few days to months.

Chemical Equilibrium and Le Chatelier’s Principle — Chemistry Study Guide Reversible reactions: Write both forward and reverse equations; equilibrium is dynamic (reactions don’t stop) Equilibrium constant expressions: Kc = [products]^coeff / [reactants]^coeff; Kp for gaseous systems Homogeneous vs heterogeneous equilibrium: Same phase vs different phases; pure solids/liquids omitted from K expression Le Chatelier’s applications: — Concentration changes: Add reactant → shifts right (toward products); remove product → shifts right — Temperature changes: Exothermic + heat → shifts left; Endothermic + heat → shifts right — Pressure changes: Increase pressure → shifts toward fewer gas moles; decrease pressure → shifts toward more gas moles Catalyst: Does NOT shift equilibrium — only speeds up both forward and reverse equally

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🔴 Extended — Deep Study (3mo+)

Comprehensive coverage for students on a longer study timeline.

Chemical Equilibrium and Le Chatelier’s Principle — Comprehensive Chemistry Notes Dynamic equilibrium: Molecules continue reacting even at equilibrium — rates are equal, not reactions stopped Equilibrium constant derivations: Relationship between Kc and Kp via Kp = Kc(RT)^Δn Reaction quotient (Q): Compare Q with K to predict direction of shift — Q < K: Reaction shifts forward (toward products) — Q = K: Already at equilibrium — Q > K: Reaction shifts reverse (toward reactants) Le Chatelier’s industrial applications: — Haber process (N₂ + 3H₂ ⇌ 2NH₃): High pressure, moderate temperature, catalyst shifts equilibrium right — Contact process (2SO₂ + O₂ ⇌ 2SO₃): Catalytic oxidation of SO₂ to SO₃ for sulfuric acid production Van’t Hoff equation: Relationship between K and temperature for endothermic/exothermic reactions Effect of inert gas: Adding inert gas at constant volume → no change in equilibrium position

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