Final answer:
To calculate the total pressure at equilibrium for the reaction given an initial pressure and the equilibrium constant Kp, an ICE table is used to determine the changes in pressures as the system reaches equilibrium. Solving for the pressures at equilibrium allows for calculating the total pressure at that point.
Step-by-step explanation:
The student asks how to calculate the total pressure at equilibrium for the reaction PCl3(g) + Cl2(g) ⇒ PCl5(g), given an initial pressure of PCl5 and the equilibrium constant Kp = 375. We start by setting up an ICE table to find the equilibrium partial pressures of each species involved in the reaction.
Step 1: Initial Pressures
Initial pressures are PCl3 = 0 bar, Cl2 = 0 bar, PCl5 = 0.0520 bar.
Step 2: Changes in Pressure
As the reaction approaches equilibrium, PCl5 will decompose into PCl3 and Cl2, thus the pressure of PCl5 decreases by x, and the pressures of PCl3 and Cl2 each increase by x.
Step 3: Equilibrium Pressures
At equilibrium, we have PCl3 = x bar, Cl2 = x bar, PCl5 = 0.0520 - x bar.
Step 4: Kp Expression
Kp = (PCl5)/(PCl3 * Cl2) = 375.
Step 5: Solve for x
By substituting the equilibrium pressures into the Kp expression, we can solve for x.
Step 6: Calculate Total Pressure
The total pressure at equilibrium is the sum of the partial pressures of PCl3, Cl2, and PCl5, which is (x + x + 0.0520 - x).