Question

A gold sample contains 90% of gold and the rest copper. How many atoms of gold are present in one gram of this sample of gold?

Answer 1

Mass of sample = 1 g

Mass of gold = 90% of the mass of sample = 90% of 1 g = 0.9 g

Number of atoms = (mass of gold/molar mass of gold) x avogardo's number

=(0.9/197) x 6.023 x 10²³