Answer:
Step-by-step explanation:
To calculate the equilibrium partial pressures of the reactants and products in a chemical reaction, we need to use the given equilibrium constant (Keq) and the initial partial pressure of one of the substances. The reaction you provided is:
PCl₅ (g) ⇌ PCl₃ (g) + Cl₂ (g)
The equilibrium constant expression for this reaction is:
Keq = [PCl₃] * [Cl₂] / [PCl₅]
Given that Keq = 0.0121 and the initial partial pressure of PCl₅ is 0.123 atm, we need to find the equilibrium partial pressures of PCl₃ and Cl₂.
Let's assume that at equilibrium, the partial pressure of PCl₃ is x atm and the partial pressure of Cl₂ is also x atm.
We can set up an expression for Keq using these values:
0.0121 = (x) * (x) / (0.123)
Now we can solve for x:
0.0121 = x² / 0.123
x² = 0.0121 * 0.123
x² = 0.0014883
x = √(0.0014883)
x ≈ 0.03856 atm
So, the equilibrium partial pressures of PCl₃ and Cl₂ are both approximately 0.03856 atm.
Now, we need to calculate the equilibrium partial pressure of PCl₅, which will be the initial partial pressure minus the change in PCl₅:
Equilibrium PCl₅ = Initial PCl₅ - Change in PCl₅
Equilibrium PCl₅ = 0.123 atm - x
Equilibrium PCl₅ = 0.123 atm - 0.03856 atm
Equilibrium PCl₅ ≈ 0.08444 atm
Therefore, the equilibrium partial pressures in the 3.00 L vessel are approximately:
PCl₃: 0.03856 atm
Cl₂: 0.03856 atm
PCl₅: 0.08444 atm