Final answer:
The reaction order in N₂ is second order based on the given rate law. In a separate reaction, we find that the order is second with respect to NO and first order with respect to H₂, making the overall reaction order third.
Step-by-step explanation:
The reaction order in N₂ according to the rate law rate = k[N₂]² [H₂]² is second order, as indicated by the exponent of 2 next to the [N₂] concentration. This means that the rate of reaction is proportional to the square of the concentration of nitrogen gas (N₂).
For the reaction H₂(g) + 2NO(g) → N₂O(g) + H₂O(g), which has been determined to have a rate law of rate = k[NO]²[H₂], the order with respect to NO is second (as indicated by the exponent 2 next to [NO]) and first order with respect to H₂ (as indicated by the absence of an exponent, which implies 1). This makes the overall reaction order third, due to the sum of the exponents for each reactant (2 + 1 = 3).
The reaction order with respect to N₂ can be determined by looking at the exponent of [N₂] in the rate law. In this case, the rate law is rate = k[N₂]² [H₂]², meaning that the reaction is second order with respect to N₂. This is because the exponent of [N₂] is 2, indicating that the reaction rate is proportional to the square of the concentration of N₂.