The remaining values of C*-C have been calculated for you. The values of C*-C have then been plotted on the same axes as the concentration-time curve and the best fit line drawn - this is the residuals graph, drawn in red.

Looking at the residuals graph, you can see that it forms a straight line. This tells you that absorption IS a first order process.

You can therefore use the residuals graph to find the absorption half-life, and from this, the absorption rate constant.

Turn to the next page to find the absorption half-life.