Question

what is Rate Law expression

Answer 1

The rate law is an expression indicating how the rate depends on concentration of the reactant and catalyst. The power of the concentration in rate expression, is called the order with respect to reactant or catalyst.

Answer 2

Rate law is the expresaion which tells about the rate at which reactants react to form a product...

Some chemical reaction takes time to complete some reaction occur at instant....This sitiation tell about the speed of reaction as some reactions are slow and some are fast....

As we can measure how fast or slow a body by measuring the speed....similarly we can measure the how fast or slow reation is...This is nothing just a rate of chemical reaction...

and This situation is expressed using an expression called rate law expression...

d[ R ] / dt = - change in reactants / change in time = change in products / change in time

A + B => C
then
d ( R ) / dt = ( - ) d (A) / dt = d ( C ) / dt