Which of the following correctly describes how rate laws are determined?
rate laws can be determined from the coefficients of balanced equations.
the rate law for an elementary step can only be determined from unimolecular reactions.
the rate law for the overall reaction is always determined by the rate law of the fastest step.
rate laws are determined through experimentation.

Rate laws are determined through experimentation.

Explanation:

Elementary reactions are reactions which takes place in single step. For elementary reactions the order is same as the stoichiometric coefficients.

For a complex reaction, the rate is determined by the slowest step.

Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.

k= rate constant

x = order with respect to A

y = order with respect to AB

n = x+y = Total order

while cooking a piece of 1/2 pound beef steak, a cast iron pan (2.4kg in weight) was heated 260 celsius.