The initial concentration for the compounds involved in the reaction displayed were determined to be [PCl5(g)] = 0.4107 mol/L, [PCl3(g)] = 0.3463 mol/L, [Cl2(g)] = 0.04085 mol/L. Calculate the value of the equilibrium constant (Kc) at 191.0 °C if the equilibrium concentration of PCl3(g) was 0.3449 mol/L.
PCl5(g) = PCl3(g)+Cl2(g)
.......PCl5(g) ==> PCl3(g) + Cl2(g)
I...0.4107........0.3463....0.04085
C......-x...........x.........x
C...0.4107-x.....0.3463+x..0.04085+x
The problem tells you that
(PCl3) = 0.3449 and that according to the table = 0.3463+x; therefore,
0.3463+x = 0.3449. That lets you solve for x and that allows you to fill in all of the other concns. Then subtitute thee concns into Kc expression and evaluate Kc. Post your work if you get stuck. I'll be happy to check your answer for you if you wish.