AP Chemistry
posted by Matt .
Given: 2N2(g) +O(2) > 2N2O(g) Kc =1.2x10^(35)
N2O4(g) > 2NO2(g) Kc = 4.6x10^(3)
1/2N2(g) + O2(g) > NO2(g) Kc= 4.1x10^(9)
Calculate Kc for the reaction between one mole of dinitrogen oxide gas and oxygen gas to give nitrogen tetroxide gas.

I got 1054.9 as my answer. I reversed the first eq and did (1/K1^(1/2)) added it to reverse of second eq (1/K2) then added that to the 3rd eq times 2 (K3^2). This got me the right equation. Do I just multiply the new Kc values together to get the final Kc of the new equation?