A flask is charged with 1.500 atm of N2O4 and 1.00 atm NO2 at 25 _x001F_C, and the following equilibrium is achieved: N2O4(g) ⇌ 2 NO2(g). After equilibrium is reached, the partial pressure of NO2 is 0.512 atm. (b) Calculate the value of Kp for the reaction. (c) Calculate Kc for the reaction.

Name: Chemistry: The Central Science
Author: Brown
ISBN: 9780137542970

Verified step by step guidance

Identify the initial conditions and changes in the system: Initially, the partial pressures are 1.500 atm for N2O4 and 1.00 atm for NO2. At equilibrium, the partial pressure of NO2 is 0.512 atm.

Determine the change in pressure for NO2: Since the initial pressure of NO2 is 1.00 atm and it decreases to 0.512 atm at equilibrium, the change in pressure for NO2 is 1.00 atm - 0.512 atm.

Use the stoichiometry of the reaction to find the change in pressure for N2O4: Since the reaction is N2O4(g) ⇌ 2 NO2(g), the change in pressure for N2O4 is half of the change in pressure for NO2.

Calculate the equilibrium pressure of N2O4: Subtract the change in pressure from the initial pressure of N2O4 to find its equilibrium pressure.

Calculate Kp using the equilibrium pressures: Use the expression Kp = (P_NO2^2) / (P_N2O4) where P_NO2 and P_N2O4 are the equilibrium partial pressures of NO2 and N2O4, respectively.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Equilibrium Constant (Kp)

The equilibrium constant Kp is a measure of the ratio of the partial pressures of the products to the reactants at equilibrium for a gas-phase reaction. It is expressed in terms of the partial pressures raised to the power of their coefficients in the balanced chemical equation. For the reaction N2O4(g) ⇌ 2 NO2(g), Kp can be calculated using the formula Kp = (P_NO2^2) / (P_N2O4), where P represents the partial pressures of the gases involved.

Relationship between Kp and Kc

Kp and Kc are related equilibrium constants for gas-phase reactions, where Kp is based on partial pressures and Kc is based on concentrations. The relationship is given by the equation Kp = Kc(RT)^(Δn), where R is the ideal gas constant, T is the temperature in Kelvin, and Δn is the change in moles of gas (moles of products minus moles of reactants). This relationship allows for the conversion between the two constants depending on the information available.

Partial Pressure

Partial pressure is the pressure exerted by a single component of a gas mixture. It is a crucial concept in understanding gas behavior and equilibrium, as it allows for the calculation of equilibrium constants. In the context of the given reaction, the partial pressures of N2O4 and NO2 at equilibrium are used to determine Kp, reflecting how the concentrations of each gas influence the overall equilibrium state.

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Textbook Question

Indicate whether each of the following statements about the reaction quotient Q is true or false: (b) If 𝑄_𝑐< 𝐾_𝑐, the reaction needs to proceed to the right to reach equilibrium.

Textbook Question

Phosphorus trichloride gas and chlorine gas react to form phosphorus pentachloride gas: PCl₃(𝑔) + Cl₂(𝑔) ⇌ PCl₅(𝑔). A 7.5-L gas vessel is charged with a mixture of PCl₃(𝑔) and Cl₂(𝑔), which is allowed to equilibrate at 450 K. At equilibrium the partial pressures of the three gases are 𝑃_PCl3= 0.124 atm, 𝑃_Cl2= 0.157 atm, and 𝑃_PCl5= 1.30 atm. (a) What is the value of 𝐾_𝑝 at this temperature?

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Textbook Question

Indicate whether each of the following statements about the reaction quotient Q is true or false: (a) The expression for 𝑄_𝑐 looks the same as the expression for 𝐾_𝑐.