In the reaction PCl5(g) ---> PCl3(g) + Cl2 (g)

0.200 mol of PCl5 is introduced into a 2.00 liter vessel.
At equilibrium, the concentration of Cl2 is found to be 0.0500 molar.
Find Kc for the reaction.

4 answers

kc= [.05][.05]/(.2/2 -.05)
how did u get that equation
It is hardly an equation.

What is the definition of Kc?
why is PCl5 .1 -.o5 that's what i don't understand i know its .1 bec of the molar but why minus .05 shouldnt it be something close to .1