what is the mass in grams of 1.20 X 10^8 atoms of copper?
1 mole of copper=6.02 X 10^23 atoms, but the molar mass of copper is 63.55 gm/mole
1.2 X 10^8 / 6.02 X 10^23=1.99335 X 10^-16 X 63.55=1.26677 X 10^-14 grams
