Phosgene is a potent chemical warfare agent that is now outlawed by international agreement. It decomposes by the reaction CoCl2(g)=Co(g) + Cl2(g), Kc=8.3×10^-4.calculate [CoCl2] when 0.100mol CoCl2 decomposes and reach equilibrium in a 10L flask

Question

Phosgene is a potent chemical warfare agent that is now outlawed by international agreement. It decomposes by the reaction CoCl2(g)=>Co(g) + Cl2(g), Kc=8.3×10^-4.calculate  [CoCl2] when 0.100mol CoCl2 decomposes and reach equilibrium in a 10L flask

bobpursley · Answer

kc=x^2/(.1/10 -x)
so you get a quadratic.
.01*8.3E-4 -8.3xE-4= x^2
x^2+ 8.3xE-4 -8.3E-6 =0
solve for x
I get two roots:
-0.014161118818594, 0.0058611188185937
ignore the negative root, so the conc is 5.86E-3 moles/liter

check my work https://www.mathsisfun.com/quadratic-equation-solver.html