Decomposition of Butadiene

Kurt Bryan and SIMIODE

This is a Mathematica notebook to illustrate the analysis of data concerning the decomposition of butadiene.

The times at which concentration data was taken (seconds):

times ={0,1000,1800,2800,3600,4400,5200,6200}

The measured concentration (moles per liter) at each time:

data = {0.01,0.00625,0.00476,0.0037,0.00313,0.0027,0.00241,0.00208}

Make a logarithmic transformation of the concentrations

logdata=Log[data]

And plot (first install into 2 x 6 matrix "pdata"):

pdata = Transpose[{times,logdata}];
plt1=ListPlot[pdata,AxesLabel->{"time (seconds)","log(concentration)"},AxesOrigin->{0,-4.5}]

This is not a straight line, so this is not first order. Still, fit a line and see how it looks

line = Fit[pdata, {1, x}, x]

Evaluate line at each time, superimpose a graph of the line on a plot with the log data

plt2=Plot[line,{x,0,6200},PlotStyle->{Red}];
Show[plt1,plt2,AxesLabel->{"time (seconds)","log(concentration)"},AxesOrigin->{0,-4.5}]

Perhaps it's second order...