For practical calculations, logarithms to base 10 are easier to use than natural logarithms.
Since In = 2.303 log ,

= -2.303 RT log
and
= 10

At 298K, 2.303 RT = 2.303 x 1.987 x 298 cal = 1364 cal = 1.364 kcal; therefore

(298) = -1.364 log
and
= 10
(Remember that the 1.364 kcal factor is valid only at 298K.)
This logarithmic relationship between and is shown in the two graphs on the right of this page. First, is plotted directly against . The range of variation in is so extreme that the graph is readable only over a limited region. A better representation is then given, with log , plotted against . As the equations predict, this is a straight line with a negative slope.