Answer
See explanation below.
Work Step by Step
Moles give us a consistent method to convert between atoms/molecules and grams.
Chemical reactions often take place at levels where using grams wouldn't make sense, yet using absolute numbers of atoms/molecules/ions would be confusing, too.
Like all units, a mole has to be based on something reproducible. A mole is the quantity of anything that has the same number of particles found in 12.000 grams of carbon-12. That number of particles is Avogadro's Number, which is roughly 6.02x10^23. A mole of carbon atoms is 6.02x10^23 carbon atoms.
