3.1.10.2 Calculations Involving Kp

• $K_{c}$ is the equilibrium constant expressed in terms of molar concentrations
• The ideal gas constant is denoted by the letter R
• If $\Delta n$ is positive, $K_{p}$ is greater than $K_{c}$


  True
• Air is an example of a homogeneous mixture
• What does the equilibrium constant, denoted as K, measure?

  Extent of reaction
• What is the relationship between K_{p}</latex> and $K_{c}$?


  $K_{p} =$$K_{c}(RT)^{\Delta n}$
• $K_{p}$ is defined using partial pressures, while $K_{c}$ uses molar concentrations.


  True
• What is a homogeneous system?

  Uniform composition
• Give an example of a homogeneous system.

  Air
• What does Dalton's Law of Partial Pressures state?

  Total pressure is sum of partial pressures
• What is the partial pressure of nitrogen in the example given at a total pressure of 200 kPa?

  80 kPa
• The equilibrium constant expressed in terms of partial pressures is called Kp
• The change in the number of moles of gaseous species is represented by Δn
• The units of Kc depend on the reaction
• Match the examples with their type of system:

  Air ↔️ Homogeneous gas

  Alloy ↔️ Homogeneous solid

  Aqueous solution ↔️ Homogeneous liquid
• In the Kp expression, partial pressures are raised to the power of their stoichiometric coefficients.

  True
• How is Kp calculated using partial pressures for the reaction $N_{2}(g) +$$3H_{2}(g) \rightleftharpoons 2NH_{3}(g)$?


  $K_{p} =$$\frac{P_{NH_{3}}^{2}}{P_{N_{2}} \times P_{H_{2}}^{3}}$
• What is the expression for $K_{p}$ in the reaction $N_{2}(g) +$$3H_{2}(g) \rightleftharpoons 2NH_{3}(g)$?


  $K_{p} =$$\frac{P_{NH_{3}}^{2}}{P_{N_{2}} \times P_{H_{2}}^{3}}$
• Steps for using the RICE table method to calculate equilibrium partial pressures

  1️⃣ Write the balanced chemical equation

  2️⃣ Note the initial partial pressures

  3️⃣ Determine the change in partial pressures

  4️⃣ Calculate the equilibrium partial pressures
• Match the equilibrium constant type with its definition:

  Kp ↔️ Equilibrium constant in terms of partial pressures

  Kc ↔️ Equilibrium constant in terms of molar concentrations
• To write the expression for $K_{p}$, raise each partial pressure to the power of its stoichiometric coefficient in the balanced equation.
• The equilibrium constant $K_{p}$ is expressed in terms of the partial pressures of the products and reactants at equilibrium
• Match the chemical species with its stoichiometric coefficient in the reaction $2N_{2}O_{5}(g) \rightleftharpoons 4NO_{2}(g) +$$O_{2}(g)$


  $N_{2}O_{5}$ ↔️ 2

  $NO_{2}$ ↔️ 4

  $O_{2}$ ↔️ 1
• Dalton's Law of Partial Pressures states that the total pressure of a gas mixture is equal to the sum of the partial pressures
• The partial pressure is the pressure exerted by an individual gas
• The equilibrium constant $K_{p}$ is used to determine the extent of a chemical reaction at equilibrium
• For the reaction N_{2}(g) + 3H_{2}(g) \rightleftharpoons 2NH_{3}(g)</latex>, the $K_{p}$ expression is $K_{p} =$$\frac{P_{NH_{3}}^{2}}{P_{N_{2}} \times P_{H_{2}}^{3}}$, and its value is 0.000926
• $K_{p}$ is calculated as the ratio of the products to reactants, with each raised to its stoichiometric
• What is the purpose of the RICE table method in equilibrium calculations?

  Organizes changes in pressures
• Match the terms with their definitions:

  $K_{p}$ ↔️ Equilibrium constant in terms of partial pressures

  $K_{c}$ ↔️ Equilibrium constant in terms of molar concentrations

  $\Delta n$ ↔️ Change in the number of moles of gaseous species

  $R$ ↔️ Ideal gas constant
• For the reaction 2SO_{2}(g) + O_{2}(g) \rightleftharpoons 2SO_{3}(g)</latex>, the value of $\Delta n$ is -1.


  True
• The relationship between $K_{p}$ and K_{c}</latex> is given by $K_{p} =$$K_{c}(RT)^{\Delta n}$


  True
• Match the type of equilibrium constant with its definition:

  $K_{p}$ ↔️ Equilibrium constant in terms of partial pressures

  $K_{c}$ ↔️ Equilibrium constant in terms of molar concentrations
• $K_{p}$ is applicable to homogeneous gas-phase reactions only
• Homogeneous systems have no phase boundaries.


  True
• $K_{p}$ is the equilibrium constant expressed in terms of partial pressures.
• $\Delta n$ represents the change in the number of moles of gaseous species.
• Match the equilibrium constant with its definition:

  Kp ↔️ Partial pressures

  Kc ↔️ Molar concentrations
• In a homogeneous system, all components exist in the same phase.


  True
• Steps to write the expression for $K_{p}$ from a balanced chemical equation:


  1️⃣ Write the equilibrium expression with products over reactants.

  2️⃣ Raise each partial pressure to the power of its stoichiometric coefficient.

  3️⃣ Ensure units are dimensionless if $\Delta n$ is zero.