We will start finding the molar mass of CuO. If we look at the the periodic table we will find the atomic masses of the elements of our compound.
Cu = 63.55 amu
O = 16.00 amu
Cu1O has one atom of Cu and one atom of O. So the molar mass is:
molar mass of Cu1O = atomic mass of Cu * 1 + atomic mass of O * 1
molar mass of Cu1O = 63.55 + 16.00
molar mass of Cu1O = 79.55 g/mol
Now that we know that the mass of one mol of Cu1O is 79.55 g, we can find the number of moles that we have in the sample. The sample has a mass of 660.12 g.
number of moles of Cu1O = mass of the sample / molar mass of Cu1O
number of moles of Cu1O = 660.12 g / (79.55 g/mol)
number of moles of Cu1O = 8.2982 moles
I have 8.2982 moles of Cu1O in the sample.