(PhysChemBasics#9) The concentration of a reactant can act on the reaction rate in different ways. This is quantified by the reaction order. Depending on the reaction order, there are different rate laws, concentration-time functions and half-lives. A reaction can be microscopically illustrated by the reaction coordinate diagram (energy profile). Its maximum - the transition state - is relevant for the reaction rate. With the Arrhenius equation we can quantify the influence of temperature on the reaction rate. We obtain the kinetic parameters of activation energy and frequency factor by evaluating the data using the Arrhenius plot. If we know the parameters, we can determine rate constants, conversion rates and reaction times for any temperature. Influences on reaction rate by catalysts, solvents and ionic strength may be quantified by Eyring's transition state theory.