4.4 Equilibria

• At equilibrium, the concentrations of all substances remain constant over time.


  True
• What three factors affect the position of equilibrium?

  Temperature, pressure, concentration
• At chemical equilibrium, the rates of the forward and reverse reactions are equal
• For reactions involving gases, an increase in pressure shifts the equilibrium towards fewer gas molecules.


  True
• A catalyst increases the rate of both the forward and reverse reactions without shifting the equilibrium position
• Increasing the pressure in a reaction with fewer gas molecules shifts the equilibrium towards the products
• At chemical equilibrium in a reversible reaction, the rates of the forward and reverse reactions are equal
• At equilibrium, the concentrations of reactants and products remain constant over time.


  True
• Increasing the temperature for an endothermic reaction shifts the equilibrium towards the products.

  True
• K = \frac{[C]^{c}[D]^{d}}{[A]^{a}[B]^{b}}</latex>, where [A] and [B] are the equilibrium concentrations of the reactants
• What does K = 1 indicate about the equilibrium position?

  Equilibrium is at a midpoint
• What is the state of chemical equilibrium defined as?

  Forward and reverse reactions occur at the same rate
• At chemical equilibrium, the rates of the forward and reverse reactions are equal
• What does the reverse reaction drive towards in a reversible reaction?

  Reactant regeneration
• What happens to the concentration of reactants at equilibrium?

  Remains constant
• In the exothermic reaction 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) + Heat, what happens if temperature increases?

  Equilibrium shifts towards reactants
• What happens to the equilibrium of an exothermic reaction if temperature decreases?

  Shifts towards products
• The equilibrium constant (K) is defined as the ratio of product concentrations to reactant concentrations
• What does a K value less than 1 indicate about the equilibrium position?

  Equilibrium favors reactants
• If K > 1, the equilibrium favors the reactants

  False
• What is the basis of Kp?

  Partial pressures
• A reversible reaction can occur in both the forward and reverse
• The values $K_{c}$ and $K_{p}$ are used to interpret equilibrium constants
• Match the forward reaction with its characteristic at equilibrium:

  Rate of Reaction ↔️ Equal to reverse reaction rate

  Concentration of Products ↔️ Remains constant over time

  State of System ↔️ Dynamic equilibrium
• What happens to the equilibrium position in an exothermic reaction when temperature increases?

  Shifts towards reactants
• For an exothermic reaction, increasing the temperature shifts the equilibrium towards the reactants.


  True
• For an endothermic reaction, increasing the temperature shifts the equilibrium towards the reactants.

  False
• In a reversible reaction, reactants are converted into products in the forward reaction.


  True
• Order the characteristics of a system at chemical equilibrium:

  1️⃣ Rates of forward and reverse reactions are equal

  2️⃣ Concentration of reactants is constant

  3️⃣ Concentration of products is constant

  4️⃣ System is in a dynamic state
• What is the key principle of Le Châtelier's principle?

  Counteracting changes
• What is the equilibrium constant (K) defined as?

  Ratio of product to reactant concentrations
• If K > 1, the equilibrium favors the products.


  True
• Equilibrium constants depend only on temperature and are not affected by pressure or concentration changes.

  True
• What is a reversible reaction?

  A reaction in both directions
• At chemical equilibrium, there is no net change in reactant or product concentrations.


  True
• Arrange the characteristics of equilibrium for the forward and reverse reactions:

  1️⃣ Rate of reaction: Equal to reverse reaction rate ||| Rate of reaction: Equal to forward reaction rate
• Match the factor affecting equilibrium with its effect on the forward reaction:

  Concentration ↔️ Increases the rate

  Temperature ↔️ Shifts towards products for exothermic reactions

  Pressure ↔️ Shifts towards fewer gas molecules
• For an exothermic reaction, increasing temperature shifts the equilibrium towards the reactants.


  True
• In the exothermic reaction 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) + Heat, what happens if pressure increases?

  Equilibrium shifts right
• If K > 1, the equilibrium favors the products.


  True