•The mass of an atom is unbelievably small (e.g. a C atom weighs 1.99 x 10-23 g)
•So kg and g are out!
•We need a new unit small enough to deal with these tiny guys reasonably •Chemists use the atomic mass unit (amu)
•1 amu = 1.66 X 10-24 g
•atoms will weigh so many amu’s
•now back to atoms and counting by weighing…