For a mass of #1*g# with respect to hydrogen atoms, and a mass of #63.5*g# with respect to copper atoms, how do the numbers of each sets atoms compare?
There are the same number of atoms in each sample.
It is a fact that if there is a mass of approximately 1.01 g of hydrogen atoms, there are Avogadro's number of hydrogen ATOMS. It is also a fact that Avogadro's number of copper atoms have a mass of 63.55 g. Both quantities represent a mole of stuff. This is a very important result to get your head around.
The number of atoms would be the same.
There are 6.023 X 10^23 atoms in 1 mole of any substance. Since the atomic mass is also equal to 1 mole and 1.01 is the atomic mass of hydrogen and 63.55 is the atomic mass of copper, both have 6.023 X 10^23 atoms (Avogadro's number).