text: The natural logarithm of the power-law rate equation is
  This can be used to estimate the order of reaction of each reactant. For example, the initial rate can be measured in a series of experiments at different initial concentrations of reactant  with all other concentrations  kept constant, so that 
  The slope of a graph of  as a function of  then corresponds to the order  with respect to reactant .
  However, this method is not always reliable because
  # measurement of the initial rate requires accurate determination of small changes in concentration in short times (compared to the reaction half-life) and is sensitive to errors, and 
  # the rate equation will not be completely determined if the rate also depends on substances not present at the beginning of the reaction, such as intermediates or products.