AP Chemistry Flashcards: Direction Of Reversible Reactions

What this deck covers

This deck focuses on Direction Of Reversible Reactions, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the effect of compressing a gaseous equilibrium system?

Answer: Shifts toward the side with fewer moles of gas. Compression increases pressure, favoring the side with fewer gas moles.

Flashcard 2: How does an increase in temperature affect $K_c$ for an endothermic reaction?

Answer: $K_c$ increases. Higher temperature favors the endothermic direction.

Flashcard 3: What is the effect of adding a pure solid to a reaction at equilibrium?

Answer: No effect on the equilibrium position. Pure solids have constant activity and don't appear in $K_c$.

Flashcard 4: What does the double arrow in a chemical equation signify?

Answer: The reaction is reversible. Double arrows indicate the reaction can proceed in both directions.

Flashcard 5: How does a change in concentration affect the value of $K_c$?

Answer: It does not change the value of $K_c$. $K_c$ depends only on temperature, not concentration changes.

Flashcard 6: What is the effect of increasing temperature on $K_c$ for an exothermic reaction?

Answer: $K_c$ decreases. Higher temperature shifts equilibrium away from the exothermic direction.

Flashcard 7: What is the primary factor affecting the magnitude of $K_c$?

Answer: Temperature. Only temperature changes affect the equilibrium constant value.

Flashcard 8: What happens to equilibrium if the volume of a gaseous system is decreased?

Answer: Shifts toward the side with fewer moles of gas. Higher pressure favors the side with fewer gas molecules.

Flashcard 9: How does decreasing the volume of a gaseous system affect equilibrium?

Answer: Shifts toward the side with fewer moles of gas. Reduced volume increases pressure, favoring fewer gas molecules.

Flashcard 10: What does it mean if $Q = K_c$ for a reaction?

Answer: The reaction is at equilibrium. Forward and reverse reaction rates are equal, no net change.

Flashcard 11: What is the effect of a catalyst on the rate of reaching equilibrium?

Answer: Increases the rate but does not change the position. Catalyst accelerates approach to equilibrium without changing final position.

Flashcard 12: What type of reaction is $N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$?

Answer: A reversible reaction. Double arrows indicate the reaction proceeds in both directions.

Flashcard 13: What happens to equilibrium when the concentration of a product is increased?

Answer: Shifts equilibrium to the left. System consumes excess product by favoring the reverse reaction.

Flashcard 14: What is the unit for the equilibrium constant, $K_c$?

Answer: Unitless. Concentration units cancel out in the equilibrium expression.

Flashcard 15: What does $\Delta n$ represent in the $K_c$ to $K_p$ conversion?

Answer: Change in moles of gas: (moles of gaseous products) - (moles of gaseous reactants). Difference in moles of gaseous species between products and reactants.

Flashcard 16: How does an increase in temperature affect $K_c$ for an endothermic reaction?

Answer: $K_c$ increases. Higher temperature favors the endothermic direction.

Flashcard 17: What is the equilibrium constant expression for $aA + bB \rightleftharpoons cC + dD$?

Answer: $K_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}$. Products raised to stoichiometric powers divided by reactants raised to powers.

Flashcard 18: Identify the effect of decreasing temperature on an exothermic reaction.

Answer: Shifts equilibrium to the right. Heat is a product, so removing heat favors product formation.

Flashcard 19: Identify the effect of increasing temperature on an endothermic reaction.

Answer: Shifts equilibrium to the right. Heat is a reactant, so adding heat favors product formation.

Flashcard 20: What is the definition of dynamic equilibrium?

Answer: Rates of forward and reverse reactions are equal. Forward and reverse reactions occur at the same rate continuously.

Flashcard 21: What is the effect of adding an inert gas at constant volume?

Answer: No effect on the equilibrium position. Inert gas doesn't change partial pressures of reactants or products.

Flashcard 22: What is the partial pressure equilibrium constant, $K_p$?

Answer: Equilibrium constant in terms of partial pressures. Uses partial pressures instead of molar concentrations.

Flashcard 23: State Le Chatelier's principle.

Answer: An equilibrium will shift to oppose changes in concentration, temperature, or pressure. System adjusts to counteract any imposed change or stress.

Flashcard 24: What effect does increasing pressure have on a gaseous reaction with fewer moles on the right?

Answer: Shifts equilibrium to the right. System minimizes pressure by favoring the side with fewer gas molecules.

Flashcard 25: How do you convert $K_c$ to $K_p$?

Answer: $K_p = K_c(RT)^{\Delta n}$. Conversion formula where $R$ is gas constant and $T$ is temperature.

Flashcard 26: How does a decrease in temperature affect $K_c$ for an exothermic reaction?

Answer: $K_c$ increases. Lower temperature favors the exothermic direction.

Flashcard 27: What happens if a catalyst is added to a reaction at equilibrium?

Answer: No effect on the equilibrium position. Equilibrium position remains unchanged with catalyst addition.

Flashcard 28: What does it mean if $Q < K_c$ for a reaction?

Answer: The reaction will shift to the right. More products need to form to reach equilibrium.

Flashcard 29: What does it mean if $K_c$ is much greater than 1?

Answer: The equilibrium favors products. Large $K_c$ indicates products are thermodynamically favored.

Flashcard 30: Identify the effect of removing a reactant from a reversible reaction.

Answer: The equilibrium will shift to the left. System responds by consuming more products to replace removed reactant.