1. The equilibrium constant equation for the given reaction is written as follows:
Kc = [NO]^4[H2O]^6 / [NH3]^4[O2]^5
In this equation, Kc represents the equilibrium constant. The concentrations of the species involved in the reaction are written within square brackets. The coefficient in front of each species indicates the stoichiometric coefficient of that species in the balanced chemical equation.
2. The square brackets [] in the equation are used to denote the concentration of the species. Concentrations are typically expressed in moles per liter (mol/L) or molarity.