From equations 1 and 2,
CO2 CO + 1/2 O2 [Kcl = 9.1 × 10^–13 at 1000ºC] (eq. 1)
H2O H2 + 1/2 O2 [Kcl = 7.1 × 10^–12 at 1000ºC] (eq. 2)
the equilibrium constant for the reaction CO2 + H2 CO + H2O at the same temperature, is