Suppose a 500.mL flask is filled with 1.6mol of NO3 and 1.2mol of NO2 . The following reaction becomes possible: +NO3gNOg 2NO2g The equilibrium constant K for this reaction is 8.01 at the temperature of the flask. Calculate the equilibrium molarity of NO3 . Round your answer to two decimal places.

Respuesta :

Answer:

At equilibrium, the concentration of [tex]NO_{3 (g)}[/tex] is 1.60 M

Explanation:

Initial values

We have the balanced chemical reaction is:

[tex]NO_{3 (g)}[/tex] + [tex]NO_{(g)}[/tex] ⇄2[tex]NO_{2(g)}[/tex]

[tex]NO_{3 (g)}[/tex] :

[tex]\frac{1.6 mol}{0.5000L} = 3.2 M[/tex]

[tex]NO_{(g)}[/tex] :

[tex]\frac{1.2 mol}{0.5000L} = 2.4 M[/tex]

Equilibrium values

[tex]NO_{3 (g)}[/tex] and [tex]NO_{(g)}[/tex]  are going to consume, while [tex]NO_{2(g)}[/tex] is going to be produced until equilibrium is reached.

By the ICE (initial, change, equilibrium) analysis:

I: [[tex]NO_{3 (g)}[/tex]]=3.2M   ;     [[tex]NO_{(g)}[/tex]]= 2.4M    ; [[tex]NO_{2(g)}[/tex]]=0

C:  [[tex]NO_{3 (g)}[/tex]]=-x   ;     [[tex]NO_{(g)}[/tex]]= -x   ; [[tex]NO_{2(g)}[/tex]]=+2x

E:  [[tex]NO_{3 (g)}[/tex]]=3.2-x  ;     [[tex]NO_{(g)}[/tex]]= 2.4-x    ; [[tex]NO_{2(g)}[/tex]]=0+2x

Now we can use the constant information:

K=8.01

[tex]8.01=\frac{(2x)^2}{(3.2-x)(2.4-x)}[/tex]

Solving for x we have 1.6 and 9.6 as possible results. But 9.6 has no sense because the concentration left can not be negative. So x=1.6

It means that at equilibrium, the concentration of [tex]NO_{3 (g)}[/tex] is going to be 1.6 M