Frequency German physicist Heinrich Hertz. One hertz means that an event repeats once per second. If a TV has a refresh rate of 1 hertz the TV's screen will change (or refresh) its picture once a second. A previous name for this unit was cycles per second (cps). The SI unit for period is the second. A traditional unit of measure used with rotating mechanical devices is revolutions per minute, abbreviated r/min or rpm. 60 rpm equals one hertz. As a matter of convenience, longer and slower waves, such as ocean surface waves, tend to be described by wave period rather
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