When given the mass of a sample, to determine the number of moles that we have, we use the molar mass. The first step to solve this problem is to find the molar mass of Cu.
The atomic mass of Cu is 63.55 amu. Since copper is a metal, is a monoatomic element, so its formula is just Cu. So the molar mass of it is also 63.55 g/mol.
molar mass of Cu = 63.55 g/mol
Now we know that the mass of 1 mol of Cu is 63.55 g, we have to find the number of moles of Cu in a 33.1 g sample of it.
number of moles of Cu = 33.1 g * 1 mol/(63.55 g)
number of moles of Cu = 0.521 moles
Answer: the amount of copper in moles in the sample is 0.521 moles.