## Chemistry and Chemical Reactivity (9th Edition)

The slow-step is rate-determining. N2O2 is an intermediary since it's not present in the global reaction. For the slow step $r=r_S=k_S[O_2][N_2O_2]$ for the equilibrium back reaction: $r_{-F}=k_{-F}[N_2O_2]=r_F=k_F[NO]^2$ $r=k_S[O_2]r_{-F}/k_{-F}=(k_Sk_F/k_{-F})[O_2][NO_2]^2$ $r=k[O_2][NO_2]^2$