Consider the reaction below:
[tex]\[ H_2(g) + CO_2(g) \rightarrow H_2O(g) + CO(g) \][/tex]

At equilibrium at 600 K, the following are true:
[tex]\[
\begin{array}{l}
\left[ CO_2 \right] = 9.5 \times 10^{-4} \, \text{M} \\
\left[ H_2 \right] = 4.5 \times 10^{-2} \, \text{M} \\
\left[ H_2O \right] = 4.6 \times 10^{-3} \, \text{M} \\
\left[ CO \right] = 4.6 \times 10^{-3} \, \text{M}
\end{array}
\][/tex]

What is the value of the equilibrium constant for this reaction in correct scientific notation?

A. [tex]\(4.9 \times 10^{-3}\)[/tex]

B. [tex]\(4.9 \times 10^{-2}\)[/tex]

C. [tex]\(4.9 \times 10^{-1}\)[/tex]

D. [tex]\(4.9 \times 10^3\)[/tex]



Answer :

To determine the equilibrium constant [tex]\( K_c \)[/tex] for the reaction at 600 K, we will use the given equilibrium concentrations. The balanced chemical equation for the reaction is:

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

The expression for the equilibrium constant [tex]\( K_c \)[/tex] is given by the concentrations of the products divided by the concentrations of the reactants, each raised to the power of their respective coefficients in the balanced equation.

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

Substitute the given equilibrium concentrations into this expression:

[tex]\[ [CO_2] = 9.5 \times 10^{-4} \, \text{M} \][/tex]
[tex]\[ [H_2] = 4.5 \times 10^{-2} \, \text{M} \][/tex]
[tex]\[ [H_2O] = 4.6 \times 10^{-3} \, \text{M} \][/tex]
[tex]\[ [CO] = 4.6 \times 10^{-3} \, \text{M} \][/tex]

So,

[tex]\[ K_c = \frac{(4.6 \times 10^{-3})(4.6 \times 10^{-3})}{(4.5 \times 10^{-2})(9.5 \times 10^{-4})} \][/tex]

This calculation results in:

[tex]\[ K_c = \frac{(4.6 \times 10^{-3})^2}{(4.5 \times 10^{-2})(9.5 \times 10^{-4})} \][/tex]

[tex]\[ K_c = \frac{2.116 \times 10^{-5}}{4.275 \times 10^{-5}} \][/tex]

[tex]\[ K_c \approx 0.495 \][/tex]

Converting this to scientific notation, we obtain:

[tex]\[ K_c \approx 4.9 \times 10^{-1} \][/tex]

Therefore, the value of the equilibrium constant for this reaction is [tex]\( 4.9 \times 10^{-1} \)[/tex]. So, the correct answer is:

[tex]\[ 4.9 \times 10^{-1} \][/tex]