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 PPCl₃ = 0.129 atm, PCl₂ = 0.156 atm, and PPCl₅ = 1.40 atm. What is the value of Kp at this temperature? Express your answer using three significant figures.

Answer 1

Step-by-step explanation:

As the given reaction is as follows.

`PCl_(3)(g) + Cl_(2)(g) \rightleftharpoons PCl_(5)(g)`

Hence, expression for
`K_(p)` will be as follows.

`K_(p) = \frac{P_{PCl_(5)}}{P_{PCl_(3)}P_{Cl_(2)}}`

Now, putting the given values into the above formula as follows.

`K_(p) = \frac{P_{PCl_(5)}}{P_{PCl_(3)}P_{Cl_(2)}}`

=
`(1.40 atm)/(0.129 atm * 0.156 atm)`

= 69.6

Therefore, we can conclude that the value of
`K_(p)` is 69.6.