Equilibrium asked where a reaction ends up. Kinetics asks something the balanced equation cannot answer: how FAST it gets there. The rate law puts numbers on it — $r = k\,[\mathrm{A}]^{n}$, read aloud r equals k times A to the n. Four letters, four jobs. $r$ is the reaction rate, how quickly the reactant disappears, in $\mathrm{mol/(L \cdot s)}$. $[\mathrm{A}]$ — square brackets, said the concentration of A — is how much reactant is present, in mol/L. $k$ is the rate constant, the reaction's own speed rating. And $n$ is the order with respect to A: the exponent that concentration is raised to. Whichever of the four the question leaves blank is the one you solve for.

Now the sentence that separates a Grade 12 answer from a guess: the order is measured, not copied. It is fitted from rate data, and only an ELEMENTARY one-step reaction is entitled to have its orders match its coefficients. Most reactions run through several steps, and the rate law reports on the slow one — which is why fractional and even negative orders are perfectly ordinary. Read the exponent off the RATE LAW; the big number in front of the formula in the balanced equation is a stoichiometric coefficient, and it is not being asked.

One more piece of housekeeping: $k$ is constant only while the temperature holds still. Warm the flask and $k$ moves — sharply. That is the next lesson.