For the Haber process, N2(g) + 3 H2(g) ⇌ 2 NH3(g), Kp = 1.45 x 10^-5, at 500 °C. In an equilibrium mixture of the three gases at 500 °C, the partial pressure of H2 is 0.928 atm and that of N2 is 0.432 atm. What is the partial pressure of NH3 in this equilibrium mixture?