Equilibrium Constant Kp

• What is the definition of partial pressure in a gas mixture?

  The partial pressure of a gas is the pressure it would have if it alone occupied the volume of the mixture.
• How is the total pressure of a mixture of gases calculated?

  The total pressure equals the sum of the partial pressures of the individual gases.
• What is the formula for calculating partial pressure?

  Partial pressure = mole fraction x total pressure.
• How is the mole fraction of a gas defined?

  Mole fraction is the number of moles of a gas divided by the total number of moles of all gases in the mixture.
• Given a mixture with 0.2 moles N2, 0.5 moles O2, and 1.2 moles CO2, what is the total number of moles?

  Total moles = 0.2 + 0.5 + 1.2 = 1.9 moles.
• How do you calculate the mole fraction of N2 in the given mixture?

  Mole fraction of N2 = $\frac{0.2}{1.9} =$$0.105$.
• What is the partial pressure of O2 if the total pressure is 3 kPa?

  Partial pressure of O2 = $0.263 \times 3 =$$0.789 \text{ kPa}$.
• How do you calculate the unit of Kp for the reaction involving gases?

  The unit of Kp is $kPa^{-2}$.
• What happens to Kp if the reaction equation is reversed?

  The value of Kp will be the inverse of the original value.
• If 20% of N2 has reacted in the equilibrium reaction, how many moles of N2 have reacted if the initial amount is 1 mole?

  0.2 moles of N2 have reacted.
• How do you calculate the moles of H2 at equilibrium if 0.2 moles of N2 have reacted?

  Moles of H2 at equilibrium = 3.0 - (3 x 0.2) = 2.40 moles.
• What is the mole fraction of NH3 at equilibrium if the total moles are 3.6?

  Mole fraction of NH3 = $\frac{0.40}{3.6} =$$0.111$.
• How do you calculate the partial pressure of NH3 at equilibrium if the total pressure is 2 kPa?

  Partial pressure of NH3 = $0.111 \times 2 =$$0.222 \text{ kPa}$.
• What does a larger Kp value indicate about the equilibrium position?

  A larger Kp indicates a greater amount of products at equilibrium.
• How do Kc and Kp change with temperature?

  Kc and Kp only change with temperature.
• What happens to the equilibrium position if the temperature is increased in an exothermic reaction?

  The equilibrium shifts to the left, favoring the reactants.
• What is the effect of increasing pressure on the equilibrium position?

  Increasing pressure shifts the equilibrium to the side with fewer moles of gas.
• How does changing pressure affect the value of Kp?

  The value of Kp remains constant regardless of pressure changes.
• What is the Kp expression for the reaction involving N2, H2, and NH3?

  Kp = $\frac{p(NH3)^2}{p(N2) \cdot p(H2)^3}$.
• What should be ignored in the Kp expression?

  Solids, liquids, and aqueous substances should be ignored in the Kp expression.
• What are the key factors affecting Kp and equilibrium position?

  • Kp changes only with temperature.
  • Increasing temperature shifts equilibrium left for exothermic reactions.
  • Increasing pressure shifts equilibrium to the side with fewer moles of gas.
  • Kp remains constant with pressure changes.
• What is the relationship between Kp and the amount of products and reactants?

  • Larger Kp indicates more products.
  • Smaller Kp indicates more reactants.
• What is the significance of mole fractions in gas mixtures?

  • Mole fractions help calculate partial pressures.
  • They represent the proportion of a specific gas in a mixture.