Answer
$$K_p = 1.76 \times 10^{20} $$
Work Step by Step
1. Calculate $\Delta n$ (n is the amount of moles of gases):
$$\Delta n = n_{products} - n_{reactants} = 2 - 3 = -1 $$
2. Convert the temperature to Kelvin:
$$T/K = 1273 + 273.15 = 1546.15 $$
3. Calculate Kp:
$$K_p = K_c(RT)^{\Delta n} = ( 2.24 \times 10^{22} )(0.0821 \times 1546.15 )^{ -1 }$$
$$K_p = 1.76 \times 10^{20} $$
