percentage purity of a sample of gold is 80 %.how many atoms of gold are present in its 1 gram sample ? atomic mass =197 u

80% of gold means 100gram of gold is present in 100gram of solution. 100gram is solution contain 80gram of gold than one gram of solution contains.0.8gram of gold. Atomic no. of gold is 79 it means in 79gram of gold the no. of atoms is avogadro no. and hence no. of atoms in 0.8gram is 69.5 into 10raise to Power 18and this is nearly equal to 69 into 10raise to power 18this is the answer.