Reactions that have an initial acceleratory period are common in both organic and inorganic systems. The Šesták-Berggren equation,
dx/dt= -kxn(1-x)m[-ln(x)]p, with p set to zero (also called the extended Prout-Tompkins (PT) equation) is an excellent empirical kinetic law for many of these
systems. In this work, it is shown to fit both isothermal and constant heating rate pyrolysis data for a well-preserved algal
kerogen in a petroleum source rock and two synthetic polymers (polycarbonate and poly-ether-etherketone), dehydration of calcium
oxalate monohydrate, decomposition of ammonium percholorate, and diffusive release of gas implanted in materials. Activation
energies derived by non-linear regression to multiple experiments are consistent with those derived by simple isoconversional
methods. Errors caused by misapplication of first-order kinetics to single-heating-rate data are discussed briefly.