This document discusses the mole concept in chemistry. It defines atomic mass, formula mass, and molar mass. Atomic mass is a relative scale that compares atom masses to carbon-12. Formula mass is the sum of all atom masses in a compound. Molar mass is the mass in grams of one mole of a substance. A mole is defined as Avogadro's number (6.02x1023) of particles, which allows chemists to convert between number of particles and mass.