Reaction kinetics: compare question

Two gaseous decomposition reactions are studied.

Reaction 1: $\ce{N2O5 -> N2O4 + 1/2 O2}$

Reaction 2: $\ce{2NO2 -> 2NO + O2}$

For each reaction, the rate equation and a possible mechanism are given.

Reaction 1: rate $= k[\ce{N2O5}]$

Step 1: $\ce{N2O5 -> NO2 + NO3}$ (slow)

Step 2: $\ce{NO2 + NO3 -> NO + O2 + NO2}$ (fast)

Step 3: $\ce{NO + NO3 -> 2NO2}$ (fast)

Reaction 2: rate $= k[\ce{NO2}]^2$

Step 1: $\ce{2NO2 -> NO + NO3}$ (slow)

Step 2: $\ce{NO3 + NO -> 2NO2}$ (fast)

Compare the two reactions in terms of the order of reaction with respect to the reactant, the overall order, the rate-determining step, and the role of any intermediate in each mechanism.