contestada

Consider the following reaction:
Fe3+(aq)+SCN−(aq) <------> FeSCN2+(aq)
A solution is made containing an initial [Fe3+] of 1.1 x 10^−3 M and an initial [SCN−] of 7.8 x 10^−4 M . At equilibrium, [FeSCN2+]= 1.6 x 10^−4 M .
Part A) Calculate the value of the equilibrium constant (Kc).
Express your answer using two significant figures.

Respuesta :

Answer:

The value of the equilibrium constant is [tex]2.7\times 10^2[/tex].

Explanation:

[tex]Fe^{3+}(aq)+SCN^-(aq)\rightleftharpoons FeSCN^{2+}(aq)[/tex]

Initially

[tex]1.1\times 10^{-3}[/tex]       [tex]7.8\times 10^{-4}[/tex]      0

At equilibrium :

[tex](1.1\times 10^{-3}-x)[/tex]       [tex](7.8\times 10^{-4}-x)[/tex]      x

The concentration of [tex]SCN^{-}[/tex] at equilibrium is given ,x=[tex]1.6\times 10^{-3}[/tex]

The expression of an equilibrium constant is given as;

[tex]K_c=\frac{[FeSCN^{2+}]}{[Fe^{3+}][SCN^-]}[/tex]

[tex]K_c=\frac{x}{(1.1\times 10^{-3}-x)\times (7.8\times 10^{-4}-x)}[/tex]

Putting value of x:

[tex]K_c=\frac{1.6\times 10^{-3}}{(1.1\times 10^{-3}-(1.6\times 10^{-3}))\times (7.8\times 10^{-4}-(1.6\times 10^{-3}))}[/tex]

The value of the [tex]K_c[/tex]

[tex]K_c=274.53\approx 2.7\times 10^2[/tex]

The value of the equilibrium constant is [tex]2.7\times 10^2[/tex].