Consider the following reversible reaction.
[tex]C(s)+O_2(g) \leftrightarrow CO_2(g)[/tex]
What is the equilibrium constant expression for the given system?
A. [tex]K _{e q}=\frac{\left[ CO _2\right]}{[ C ]\left[ O _2\right]}[/tex]
B. [tex]K _{\text {eq }}=\frac{\left[ CO _2\right]}{\left[ O _2\right]}[/tex]
C. [tex]K _{e q}=\frac{\left[ C ^3\left[ O _2\right]\right.}{\left[ CO _2\right]}[/tex]
D. [tex]K _{e q}=\frac{\left[ O _2\right]}{\left[ CO _2\right]}[/tex]
Answer (1)
Write the general form of the equilibrium constant expression.
Note that solids do not appear in the equilibrium constant expression.
Write the final equilibrium constant expression: K e q = [ O 2 ] [ C O 2 ] .
The equilibrium constant expression for the given system is K e q = [ O 2 ] [ C O 2 ] .
Explanation
Understanding the Reaction The reaction is: C ( s ) + O 2 ( g ) ↔ C O 2 ( g ) . We need to determine the equilibrium constant expression K e q for this reaction.
Equilibrium Constant Expression The general form of the equilibrium constant expression is the ratio of the concentrations of the products to the concentrations of the reactants, each raised to the power of their stoichiometric coefficients. However, solids and pure liquids do not appear in the equilibrium constant expression because their activities are defined as 1.
Writing the Expression In this reaction, C ( s ) is a solid, so its concentration does not appear in the equilibrium constant expression. Therefore, the equilibrium constant expression is given by: K e q = [ O 2 ] [ C O 2 ] .
Examples
Understanding equilibrium constants is crucial in various real-world applications, such as optimizing industrial chemical processes. For instance, in the production of ammonia via the Haber-Bosch process, manipulating the equilibrium constant by adjusting temperature and pressure allows for maximizing ammonia yield. Similarly, in environmental science, the equilibrium constant helps predict the distribution of pollutants in different environmental compartments, aiding in the development of effective remediation strategies. This concept is also fundamental in biochemistry, where enzyme-catalyzed reactions rely on equilibrium to regulate metabolic pathways, ensuring efficient cellular function.
