Figure 2.16. Arrhenius Diagram for Calcite + Quartz = Wollastonite +CO2 . The base 10 logarithm of the reaction rate values k (in units of hour-1) from Figure 15 are shown as a function of inverse temperature (1/T) in degrees Kelvin. A straight line has been fit to the data with a slope of -5684.9 and an intercept of 4.3296 (fit R2=0.9903). Using the Arrhenius equation described in the text, the slope and intercept can be used to obtain an activation energy of 109 kJ/mol (=5684.9*2.303*R) and a pre-exponential term k0 of 21360 (=exp[4.3296*2.303]). 2.303 is the constant of conversion from natural log values to base 10 log values. The Arrhenius equation fit to these data is:

k = 21360 exp [-109000 / (RT)]

where R is the gas constant (8.314 J K-1 mol-1) and T is temperature in degrees Kelvin. Data are from Kridelbaugh (1973).