Equilibrium Concentration

[ada15]

Homework Statement

CO(g) + NH_3(g) ...> HCONH_2(g)

euilibrium constant is: K = 0.207 at 400 K
If a reaction is filled with intial concentrations 2.20 M of CO and 2.60 M of NH_3 and the reactanats are allowed to raect at 400K/ what will be the concentrations of CO at equilibrium ?

Homework Equations

Keq = [HCONH_2] / [CO] [NH_3]

The Attempt at a Solution

0.207 = (X) /(2.20-X)(2.6-X)

But I'm getting the wrong answer for x. Please help me.

 

[qwedsa]

^your equation for x seems correct. i rearranged it to
0 = 5.72/x - 5.007 + x
we need to find the zeroes

when graphed, the zeros are 1.76 and 3.24

if we use 3.24, we would have a negative concentration of both CO and NH3, which is physically impossible. so, we go with 1.76

so the answer: 2.2 M - 1.76 = 0.44 M