{
  "deck_name": "Chemical Equilibrium",
  "cards": [
    { "question": "What does it mean for a reversible reaction in a closed system to reach dynamic equilibrium?", "answer": "The forward and reverse reactions continue at equal rates, so the macroscopic amounts of reactants and products remain constant." },
    { "question": "At equilibrium, must reactant and product concentrations be equal?", "answer": "No. Their concentrations are constant at equilibrium, but they need not equal one another." },
    { "question": "For aA + bB ⇌ cC + dD, what is the concentration form of the equilibrium constant Kc?", "answer": "Kc = [C]^c[D]^d / ([A]^a[B]^b), using equilibrium concentrations and the balanced equation’s coefficients as exponents." },
    { "question": "Which substances are omitted from a standard Kc expression?", "answer": "Pure solids and pure liquids are omitted; their activities are treated as constant." },
    { "question": "What does a large K value indicate about an equilibrium mixture?", "answer": "At that temperature, products are favored at equilibrium relative to reactants; K does not describe how quickly equilibrium is reached." },
    { "question": "How does the reaction quotient Q differ from the equilibrium constant K?", "answer": "Q uses the same form as K but can be calculated from concentrations at any point, not only at equilibrium." },
    { "question": "For a reaction mixture with Q < K, which direction gives net reaction as equilibrium is approached?", "answer": "The forward direction, toward products, until Q reaches K." },
    { "question": "For a reaction mixture with Q > K, which direction gives net reaction as equilibrium is approached?", "answer": "The reverse direction, toward reactants, until Q reaches K." },
    { "question": "What relationship holds between Q and K at equilibrium?", "answer": "Q = K." },
    { "question": "For a given reaction as written, which common change can alter the value of K?", "answer": "Changing the temperature. Changing concentration, pressure, or adding a catalyst can change the mixture or its path to equilibrium, but not K at a fixed temperature." },
    { "question": "If a balanced reaction is reversed, how is its equilibrium constant related to the original K?", "answer": "The new constant is the reciprocal: K(reversed) = 1/K(original)." },
    { "question": "If every coefficient in a balanced reaction is multiplied by n, how does its equilibrium constant change?", "answer": "The new equilibrium constant is K^n." },
    { "question": "When two reactions are added to obtain an overall reaction, how are their equilibrium constants combined?", "answer": "Multiply the equilibrium constants for the component reactions." },
    { "question": "For aA + bB ⇌ cC + dD, what shift follows when more reactant A is added at constant temperature?", "answer": "The system shifts in the forward direction and consumes some added A; K remains unchanged." },
    { "question": "At constant temperature, what is the usual equilibrium response to removing a product?", "answer": "The system shifts in the forward direction to replace some of the removed product; K remains unchanged." },
    { "question": "For a gas equilibrium, what is the usual shift after compression if the two sides have different total gas coefficients?", "answer": "It shifts toward the side with fewer moles of gas. If both sides have the same number, compression does not favor either side." },
    { "question": "Does adding an inert gas at constant volume usually shift an ideal-gas equilibrium?", "answer": "No. At constant volume, the reactants’ and products’ partial pressures do not change, so the equilibrium position does not shift." },
    { "question": "For an exothermic forward reaction, which direction is favored when temperature increases?", "answer": "The reverse, endothermic direction is favored; the equilibrium constant for the forward reaction decreases." },
    { "question": "How does a catalyst affect an equilibrium system?", "answer": "It speeds up the forward and reverse reactions so equilibrium is reached sooner, but it does not change K or the equilibrium composition." },
    { "question": "What is the practical idea behind Le Châtelier’s principle?", "answer": "When an equilibrium system is disturbed, its composition shifts in a direction that partly counteracts the disturbance as a new equilibrium is established." }
  ]
}