For the reaction given below at 700°c, kc = 0.534. h2(g + co2(g h2o(g + co(g calculate the number of moles of h2 that are present at equilibrium if a mixture of 0.229 moles of co and 0.229 moles of h2o is heated to 700°c in a 11.0-l container.

Respuesta :

The balanced chemical reaction is written as:

H2 + CO2 <---> H2O + CO

To determine the moles of H2 at equilibrium, we use the ICE table as follows:

Initial concentration = 0.229/11.0 = 0.021 M

           H2O      CO         H2         CO2
I         0.021    0.021       0              0
C          -x           -x           x              x
--------------------------------------------------------
E     0.021- x  0.021-x    x              x

Kc = 0.534 = (H2)(CO2) / (H2O)(CO)
0.534 = (x)(x) / (0.021-x) (0.021-x)
x = 8.87x10^-3 M

mole H2 = 
8.87x10^-3 M (11.0 L) = 0.098 mol H2

Answer : The concentration of [tex]H_2[/tex] at equilibrium is 0.012 M

Solution :

First we have to calculate the concentration of [tex]CO[/tex] and [tex]H_2O[/tex].

Concentration of [tex]CO[/tex] = [tex]\frac{Moles}{Volume}=\frac{0.229}{11}=0.0208M[/tex]

Concentration of [tex]H_2O[/tex] = [tex]\frac{Moles}{Volume}=\frac{0.229}{11}=0.0208M[/tex]

The given equilibrium reaction is,

                            [tex]H_2O(g)+CO(g)\rightleftharpoons H_2(g)+CO_2(g)[/tex]

Initially conc.     0.0208   0.0208          0        0

At equilibrium.  (0.0208-x) (0.0208-x)  x       x

The expression of [tex]K_c[/tex] will be,

[tex]K_c=\frac{[H_2][CO_2]}{[H_2O][CO]}[/tex]

For given reaction the value of [tex]K_c[/tex] will be, [tex]\frac{1}{0.534}[/tex] (for reverse reaction).

[tex]\frac{1}{0.534}=\frac{(x)(x)}{(0.0208-x)\times (0.0208-x)}[/tex]

[tex]\frac{1}{0.534}=\frac{(x)^2}{(0.0208-x)^2}[/tex]

[tex]\frac{1}{0.534}=(\frac{(x)}{(0.0208-x)})^2[/tex]

[tex]\sqrt{\frac{1}{0.534}}=\frac{(x)}{(0.0208-x)}[/tex]

[tex]1.368=\frac{(x)}{(0.0208-x)}[/tex]

By solving the term x, we get

[tex]x=0.012[/tex]

Thus, the concentration of [tex]H_2[/tex] at equilibrium = x = 0.012 M