Question

A reaction vessel is charged with phosphorus pentachloride, which partially decomposes to phosphorus trichloride and molecular chlorine according to the following reaction:

PCl5(g)â PCl3(g)+Cl2(g)

When the system comes to equilibrium at 250.0°C, the equilibrium partial pressures are: PPCl5 = 0.688 atm and PPCl3 = PCl2 = 0.870 atm.

Required:
What is the value of Kp at this temperature?

Answer 1

Answer:

Kp = 1.10.

Explanation:

Hello there!

In this case, according to the given information about the chemical reaction at equilibrium, it turns out possible for us to find the partial pressures-based equilibrium expression for the decomposition of phosphorous pentachloride by applying the law of mass action whereas the pressure of products is divided by that of the reactants as shown below:

$Kp=\frac{p_{PCl_3}p_{Cl_2}}{p_{PCl_5}}$

Now, we plug in the given pressures to obtain:

$Kp=\frac{0.870}{0.688} \\\\Kp=1.10$

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