Phosphorus pentachloride decomposes according to the chemical equation PCl 5 ( g ) − ⇀ ↽ − PCl 3 ( g ) + Cl 2 ( g ) K c = 1.80 at 250 ∘ C A 0.1846 mol sample of PCl 5 ( g ) is injected into an empty 2.55 L reaction vessel held at 250 ∘ C. Calculate the concentrations of PCl 5 ( g ) and PCl 3 ( g ) at equilibrium.

Explanation:

Hello, in this case, considering the undergoing gaseous state chemical reaction:

And the given mole, volume and temperature, one could compute the initial concentration of phosphorus pentachloride as follows:

Next, one writes the law of mass action as follows:

Thus, by introducing the change due to the reaction extent, it becomes:

In such a way, solving for with solver or the quadratic equation, one gets:

With which it is clear the solution is 0.0697M, therefore, the equilibrium concentrations result:

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