How many moles are in 15 grams of lithium?

1. What is the atomic weight of lithium?

2. The molecular weight (of a molecule) or the atomic weight (of a monatomic element) is expressed in grams per mole (grams/mole). This is the conversion factor to go from moles to grams. Its inverse is the conversion factor to go from grams to moles:

\cancel {grams} \,\times\, \frac {moles}{\cancel {gram}} = moles

\cancel{moles} \,\times\, \frac {grams}{\cancel {mole}} = grams