# What is the difference between these systems of mass

1. Jun 20, 2009

### ronaldor9

What is the difference between amu (or u) and molar mass? It seems like these are equivalent. Could somebody explain them.

And why is it possible to calculate the number of atoms on hydrogen using this calculation:
[1.00797 amu H x 1.6605x10-27 kg/amu]-1=5.975x1026 atoms of H

2. Jun 20, 2009

### poopcaboose

I think amu is the reciprocal of avogadro's number then converted to kilograms, avogadro's number is essentially a conversion factor from atomic mass units to grams. Try converting the amu constant to grams then taking the reciprocal. Then look up avagodros number. So really they can by considered functionally equivalent.