Born May 5, 1851, in Pulsnitz, Saxony; died Dec. 1, 1916, in Dresden. German analytic chemist and chemical engineer. Pupil of R. Bunsen.
From 1879 to 1913, Hempel was a professor at the Higher Engineering School in Dresden. He devised the gas burette and pipette, the exsiccator, the calorimeter, and other instruments that are still used. Hempel developed methods of gas analysis, determined the heat of combustion of coals (from 1892), and indicated the possibility of using electrolysis of sodium chloride solutions to obtain sodium hydroxide and chlorine (1899).