So by doubling the concentration of A, we double the rate by quadrupling it, we quadruple the rate, by tripling it, we triple the rate and so forth. So if we have a direct correlation between the reactant concentration and the rate of the reaction, then that means that reactant is first order with respect to that particular reactant. Now to calculate the overall order of that particular reaction we have to sum up all the exponents in that particular chemical rate law. And so because in this particular case we only have one exponent, that means the rate, the order is first. And in this particular case the order is also first. But if we for example move on to a second order reaction, let's suppose we have A and B are the two reactants and they react to produce C. And this k value is basically the reaction constant, the rate constant.