The two common chlorides of Phosphorus, PCl3 and PCl5, both important in the production of other phosphorous compounds, coexist in equilibrium as shown in the balanced chemical reaction below:

Question

The two common chlorides of Phosphorus, PCl3 and PCl5, both important in the production of other phosphorous compounds, coexist in equilibrium as shown in the balanced chemical reaction below:
PCl3 (g) + Cl2 (g) <-----> PCl5 (g)
 
At 250 C, an equilibrium mixture in a 2.50 L flask contains 0.305 g  PCl5, 0.440 g PCl3, and 4.24 g Cl2.

A. Show the equilibrium Constant formula.

B.  What is the value of Kc for this reaction? Hint: Use molarity in the Kc calculations.

My answers:
A.
Kc = [PCl5]/([Cl2][PCl3])
B.
1.826

DrBob222 · Answer

A is OK. I don't get that for B What concns do you have for each?

Anonymous · Answer

I got 0.23887323 for Cl2, 0.001281584 for PCl3, and 0.000586862 for PCl5.

DrBob222 · Answer

Check that Cl2. 4.24/70.9.2.5 = 0.0239