Hertz Hertz The hertz (symbol: Hz) is the derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second. It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (10 Hz, kHz), megahertz (10 Hz, MHz), gigahertz (10 Hz, GHz), terahertz (10 Hz, THz), petahertz (10 Hz, PHz), and exahertz (10 Hz, EHz). Some of the unit's most common uses are in the description of sine waves and musical tones, particularly those used in radio- and
Kilocalorie per mole Kilocalorie per mole The kilocalorie per mole is a unit to measure an amount of energy per number of molecules, atoms, or other similar particles. It is defined as one kilocalorie of energy (1000 thermochemical gram calories) per one mole of substance, that is, per Avogadro’s number of particles. It is abbreviated "kcal/mol" or "kcal mol". As typically measured, one kcal/mol represents a temperature increase of one degree Celsius in one liter of water (with a mass of 1kg) resulting from the reaction of one mole of reagents. In SI units, one kilocalorie per mole is equal to 4.184 kilojoules