Equilibria (KP)

• In dynamic equilibrium, the rate of the forward reaction equals the rate of the reverse
• Equilibrium can only be reached in a closed system.
• What does the equilibrium constant, K𝒸, measure?

  Reaction extent
• A K𝒸 value less than 1 indicates that the equilibrium lies to the left.
• If K𝒸 is greater than 1, the equilibrium lies to the right
• What principle explains the effect of changing reaction conditions on equilibrium position?

  Le Chatelier's principle
• Le Chatelier's principle states that equilibrium shifts to oppose changes in conditions.
• If the concentration of reactant A is increased in the reaction A + B ⇌ C + D, the equilibrium shifts to the right.
• What happens to the equilibrium position if the pressure is increased in a reaction with fewer moles on the right side?

  Shifts right
• Increasing the temperature in an exothermic reaction causes K�� to decrease.
• What does Kₚ measure?

  Partial pressures
• Which type of substances are included in Kₚ expressions?

  Gases
• Changes in concentration and pressure affect the value of Kₚ.

  False
• Temperature is the only factor that affects the value of an equilibrium constant.
• What happens to Kₚ in an endothermic reaction if the temperature is increased?

  Increases
• In a gas mixture, the partial pressure of a gas contributes to the total pressure.
• In a gas mixture, the partial pressure of each gas is proportional to its mole fraction.
• How is the mole fraction of a gas calculated in a mixture?

  Moles of gas / total moles
• The mole fractions of all gases in a mixture always add up to 1.
• The first step in calculating Kₚ is to determine the mole fractions
• After calculating mole fractions, the next step is to calculate the partial pressures
• Steps to calculate Kₚ using initial amounts and equilibrium data:

  1️⃣ Write the balanced equation

  2️⃣ Determine initial and equilibrium moles

  3️⃣ Calculate mole fractions

  4️⃣ Calculate partial pressures

  5️⃣ Write the Kₚ expression

  6️⃣ Calculate Kₚ and its units