Identify The Correct Equilibrium Constant Expression For This Equation:$\[ 2 \text{NO}(g) + \text{O}_2(g) \leftrightarrow 2 \text{NO}_2(g) \\]A. $\[ K_{\text{eq}} = \frac{[\text{NO}]^2[\text{O}_2]}{[\text{NO}_2]^2} \\]B. $\[

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Understanding Equilibrium Constant Expression

In chemistry, the equilibrium constant expression is a mathematical representation of the equilibrium constant (K) for a given chemical reaction. It is a crucial concept in understanding the behavior of chemical systems and predicting the direction of a reaction. In this article, we will focus on identifying the correct equilibrium constant expression for a given chemical equation.

The Chemical Equation

The given chemical equation is:

2NO(g)+O2(g)↔2NO2(g){ 2 \text{NO}(g) + \text{O}_2(g) \leftrightarrow 2 \text{NO}_2(g) }

This equation represents the reaction between nitrogen monoxide (NO) and oxygen (O2) to form nitrogen dioxide (NO2).

Equilibrium Constant Expression

The equilibrium constant expression for this equation can be written as:

Keq=[NO2]2[NO]2[O2]{ K_{\text{eq}} = \frac{[\text{NO}_2]^2}{[\text{NO}]^2[\text{O}_2]} }

This expression indicates that the equilibrium constant (K) is equal to the ratio of the concentrations of the products (NO2) squared to the concentrations of the reactants (NO) squared and oxygen (O2).

Why is this the Correct Expression?

To determine the correct equilibrium constant expression, we need to consider the stoichiometry of the reaction. The balanced equation shows that 2 moles of NO react with 1 mole of O2 to form 2 moles of NO2. This means that the concentration of NO2 will be twice the concentration of NO and O2.

Using the law of mass action, we can write the equilibrium constant expression as:

Keq=[NO2]2[NO]2[O2]{ K_{\text{eq}} = \frac{[\text{NO}_2]^2}{[\text{NO}]^2[\text{O}_2]} }

This expression is consistent with the stoichiometry of the reaction and is therefore the correct equilibrium constant expression.

Common Mistakes to Avoid

When writing the equilibrium constant expression, it is essential to consider the stoichiometry of the reaction and the law of mass action. Some common mistakes to avoid include:

  • Writing the expression with the wrong stoichiometric coefficients
  • Failing to include all the reactants and products in the expression
  • Writing the expression with the wrong concentrations (e.g., using partial pressures instead of concentrations)

Conclusion

In conclusion, the correct equilibrium constant expression for the given chemical equation is:

Keq=[NO2]2[NO]2[O2]{ K_{\text{eq}} = \frac{[\text{NO}_2]^2}{[\text{NO}]^2[\text{O}_2]} }

This expression is consistent with the stoichiometry of the reaction and is therefore the correct equilibrium constant expression. By understanding the equilibrium constant expression, we can better predict the behavior of chemical systems and make more accurate predictions about the direction of a reaction.

Additional Resources

For further information on equilibrium constant expressions, we recommend the following resources:

Frequently Asked Questions

Q: What is the equilibrium constant expression?

A: The equilibrium constant expression is a mathematical representation of the equilibrium constant (K) for a given chemical reaction.

Q: How do I write the equilibrium constant expression?

A: To write the equilibrium constant expression, you need to consider the stoichiometry of the reaction and the law of mass action.

Q: What are some common mistakes to avoid when writing the equilibrium constant expression?

A: Some common mistakes to avoid include writing the expression with the wrong stoichiometric coefficients, failing to include all the reactants and products, and writing the expression with the wrong concentrations.

Q: What resources can I use to learn more about equilibrium constant expressions?

Q&A: Equilibrium Constant Expression

Q: What is the equilibrium constant expression?

A: The equilibrium constant expression is a mathematical representation of the equilibrium constant (K) for a given chemical reaction. It is a crucial concept in understanding the behavior of chemical systems and predicting the direction of a reaction.

Q: How do I write the equilibrium constant expression?

A: To write the equilibrium constant expression, you need to consider the stoichiometry of the reaction and the law of mass action. The general form of the equilibrium constant expression is:

Keq=[products]a[reactants]b{ K_{\text{eq}} = \frac{[\text{products}]^a}{[\text{reactants}]^b} }

where [products] and [reactants] are the concentrations of the products and reactants, respectively, and a and b are the stoichiometric coefficients.

Q: What are the key components of the equilibrium constant expression?

A: The key components of the equilibrium constant expression are:

  • Stoichiometric coefficients: These are the numbers in front of each reactant and product in the balanced equation.
  • Concentrations: These are the amounts of each reactant and product present in the system.
  • Law of mass action: This is the principle that the equilibrium constant is equal to the ratio of the concentrations of the products to the concentrations of the reactants.

Q: How do I determine the equilibrium constant expression for a given reaction?

A: To determine the equilibrium constant expression for a given reaction, you need to follow these steps:

  1. Write the balanced equation: Write the balanced equation for the reaction, including the stoichiometric coefficients.
  2. Identify the products and reactants: Identify the products and reactants in the balanced equation.
  3. Determine the stoichiometric coefficients: Determine the stoichiometric coefficients for each reactant and product.
  4. Write the equilibrium constant expression: Write the equilibrium constant expression using the stoichiometric coefficients and the concentrations of the reactants and products.

Q: What are some common mistakes to avoid when writing the equilibrium constant expression?

A: Some common mistakes to avoid when writing the equilibrium constant expression include:

  • Writing the expression with the wrong stoichiometric coefficients: Make sure to use the correct stoichiometric coefficients for each reactant and product.
  • Failing to include all the reactants and products: Make sure to include all the reactants and products in the expression.
  • Writing the expression with the wrong concentrations: Make sure to use the correct concentrations for each reactant and product.

Q: What resources can I use to learn more about equilibrium constant expressions?

A: You can use online resources such as ChemGuide, Khan Academy, and Wikipedia to learn more about equilibrium constant expressions.

Q: How do I use the equilibrium constant expression to predict the direction of a reaction?

A: To use the equilibrium constant expression to predict the direction of a reaction, you need to follow these steps:

  1. Write the equilibrium constant expression: Write the equilibrium constant expression for the reaction.
  2. Determine the equilibrium constant value: Determine the equilibrium constant value (K) for the reaction.
  3. Compare the equilibrium constant value to 1: Compare the equilibrium constant value to 1.
  • If K > 1: The reaction favors the products.
  • If K < 1: The reaction favors the reactants.
  • If K = 1: The reaction is at equilibrium.

Q: What are some real-world applications of equilibrium constant expressions?

A: Equilibrium constant expressions have many real-world applications, including:

  • Chemical engineering: Equilibrium constant expressions are used to design and optimize chemical processes.
  • Environmental science: Equilibrium constant expressions are used to model and predict the behavior of environmental systems.
  • Biotechnology: Equilibrium constant expressions are used to design and optimize biotechnological processes.

Conclusion

In conclusion, the equilibrium constant expression is a crucial concept in understanding the behavior of chemical systems and predicting the direction of a reaction. By following the steps outlined in this article, you can determine the equilibrium constant expression for a given reaction and use it to predict the direction of the reaction.