The order of a reaction with respect to a chemical species may be determined in two ways

• By measuring the rate of reaction at different concentrations of the chemical species with all other reagents kept constant (the experiment you performed) OR
• Measuring the concentration of the chemical species at different times within a single reaction and by plotting the decrease in concentration.

  For a order of reaction which is	zero order,	a plot of the species concentration (on y-axis) versus time (on x-axis) is a linear curve
  	first order,	a plot of the ln(concentration) (on y-axis) versus time (on x-axis) is a linear curve
  	second order,	a plot of the 1/concentration (on y-axis) versus time (on x-axis) is a linear curve

  The slope of these graphs in each case yields the rate constant of these reactions. Remember that the rate constant must be positive, so if the slope is negative, take the absolute value (just leave out the - sign)

  Heating acetylene in chloroform solution with a nickel catalyst yields benzene.

  The rate of this reaction has been studied in chloroform solution at 45^oC and the concentration of acetylene measured at selected times.

  This data is shown in the following table:

  Time (sec)	[HCCH]
  95	0.363
  336	0.270
  571	0.198
  818	0.157
  1054	0.137
  1296	0.121
  1535	0.110
  1771	0.099

  Using the EXCEL (or similar program), plot the different graphs for zero, first and second order reactions. The value r² is a measure of the linearity of the line in the graph. The graph with the linearity closest to 1 is the best-fit and thus is the correct graph with the correct order of reaction.

  (You have three chances until the answer will be given; you have already tried 0 times)

  From the appropriate plot, determine
  the order of reaction with respect to HCCH
  rate constant		mol L-1 sec-1 mol-1 L sec-1 sec sec-1