Answer:
If we know that a reaction is an elementary reaction, then we know its rate law.
Explanation:
An elementary reaction is a reaction that takes place in one reactive encounter. This means that the two species interact in a single step to give the products.
If two reactants interact in a single step to yield the products then we can easily deduce the rate law from the reaction equation.
For instance, For the reaction;
2A + B → C
The rate law is
rate = k[A]²[B].
If the reaction is an elementary reaction and the equation of the reaction is balanced, then we can deduce the rate law from the balanced reaction equation.
