The free energy of formation of nitric oxide, NO, at 1000 K (roughly the temperature in an automobile engine during ignition) is about 78 kJ/mol. Calculate the equilibrium constant K_p for the reaction N₂(g) + O₂(g) $\leftrightharpoons$ 2NO(g) at this temperature. A) K_p = 6.9 * 10^-9 B) K_p = 7.1 *10^-9 C) K_p = 7.3 * 10^-9 D) K_p = 7.5 * 10^-9 E) None of the above

Question

Quizplus · Accepted Answer

The equilibrium constant, K, for the reaction at a given temperature can be calculated using the equation:

K = e^(-ΔG°/RT)

where ΔG° is the standard free energy change, R is the gas constant, and T is the temperature in Kelvin.

Using the given information, ΔG° = 78 kJ/mol and T = 1000 K. The gas constant, R, is 8.314 J/mol·K.

Substituting these values into the equation, we get:

K = e^(-78,000 J/mol / (8.314 J/mol·K × 1000 K))

K = e^(-9.395)

K = 7.04 × 10^-5

This value should be expressed in scientific notation as 7.1 × 10^-5. Therefore, the best choice is B.

The Free Energy of Formation of Nitric Oxide, NO, at 1000