Drawing a schematic energy diagram for the decomposition of H[subscript 2]O[subscript 2] catalyzed by MnO[subscript 2] through a simple thermometric measurement outlined in this study is intended to integrate students' understanding of thermochemistry and kinetics of chemical reactions. The reaction enthalpy, delta[subscript r]H, is determined by a conventional thermometric method, where a modified calorimetric vessel with negligible thermal leakage is used. Thermometric curves for the reactions at different initial temperatures can be converted to different series of kinetic rate data under nonlinearly changing temperatures. The apparent activation energy, E[subscript a], is easily determined by the differential kinetic relationship at the fixed degree of reaction among the different series of kinetic rate data. By determination of both delta[subscript r]H and E[subscript a], students can draw a schematic diagram of the energy change accompanying the reaction. The laboratory activity and post lab data treatments are useful in general chemistry courses at the university or college level and also applicable in advanced chemistry courses in high schools. (Contains 4 figures and 1 table.)