Question

For the reaction N₂(g) + 3H₂(g) → 2NH₃(g), the equilibrium constant K_c at a certain temperature is 1.5. If the concentration of N₂ is 0.5 M, H₂ is 1.0 M, and NH₃ is 0.2 M, what is the reaction quotient Q_c?

• A. \( 1.0 \)
• B. \( 1.5 \)
• C. \( 0.5 \)
• D. \( 2.0 \)

Hint:

Remember that \( Q_c \) can be calculated in the same way as the equilibrium constant, using the concentrations of the reactants and products at any point during the reaction.

Answer 1

The Correct Option is C

Step 1: Define the reaction quotient. The reaction quotient \( Q_c \) quantifies the relative amounts of products and reactants present in a reaction at a given time. For the reaction \( \text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g) \), \( Q_c \) is calculated as: \[ Q_c = \frac{[\text{NH}_3]^2}{[\text{N}_2][\text{H}_2]^3} \] Step 2: Calculate \( Q_c \) using provided concentrations. Given the following concentrations: - \( [\text{N}_2] = 0.5 \, \text{M} \) - \( [\text{H}_2] = 1.0 \, \text{M} \) - \( [\text{NH}_3] = 0.2 \, \text{M} \) Substitute these values into the \( Q_c \) expression: \[ Q_c = \frac{(0.2)^2}{(0.5)(1.0)^3} \] Perform the calculation: \[ Q_c = \frac{0.04}{0.5} = 0.08 \] Answer: The calculated value of \( Q_c \) is \( 0.08 \). This result may indicate a discrepancy with the provided options.