INTRODUCTION CONTINUED

A graph of log concentration against time (see below left) is very useful. However, to plot the graph, you need to calculate log10 of the concentration for every point.

A quicker way to plot the results to obtain a linear graph is to plot a semilogarithmic graph in which the x-axis (time) uses a linear scale and the y-axis (concentration) uses a logarithmic scale. When you plot concentration against time, you obtain an equivalent linear graph (see below right).