(a) The slope of the reaction rate, v, versus the reactant concentration, x, scaled by both the reactant concentration and reaction rate yields the elasticity, . (b) If the log of the reaction rate and log of the reactant concentration are plotted, the elasticity can be read directly from the slope of the curve. Curves were generated by assuming . Note that we use the partial derivative notation for the slope, because the reaction rate could potentially be changed by other factors such as product which we keep constant when measuring the gradient of the response to x. (Online version in colour.)