AP Chemistry Question of the Day --67

It has been a while since I last posted an AP Chem question. I recently got an email acknowledging me that this blog is helpful. I am glad to hear it and decided to resume it. Here comes question 67.

The equilibrium constants for the following reaction:

N2(g) +O2(g) ⇄2NO(g)

are Kp=1.1e^3 at 2200K and Kp=3.6e^3 at 2500K respectively. Which of the following statement is true:

A. Higher total pressure shifts the equilibrium to the left.
B. The partial pressure of NO(g) is less at 2200K than at 2500K
C. The total pressure at 2200K is the same as at 2500K
D. The reaction is exothermic
E. Kp is less than Kc by (RT)

The correct answer is B.

Since both the reactant side and the product side have 2 moles of gas. The change in pressure or total volume will not shift the equilibrium, which eliminate A.
C sounds right but is actually wrong because as the total mole of the gases and the volume of the gases stay unchanged, the total pressure will increase as a result of the temperature change. The total pressure should be higher at 2500K than at 2200K.
As the temperature increases from 2200K to 2500K, the equilibrium constant increases, indicating the  forward reaction is endothermic.
Since there are equal number moles of gases on both sides, the Kp should be equal to Kc

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