Abstract Half-life formulas of chemical reactions not only relate with the order of reaction, but also connect with the type of reaction. Chemical reaction with the same simple order and different type may have the different half-life formulas. In this paper, half-life formulas of chemical reactions with simple order is discussed, focusing on the feature of half-life formulas of different type of chemical reactions with a second order and a third order, as well as the relationship among them.
