Question

How many atoms are in a 51 g sample of gold?

Answer 1

mass of sample of gold=591gm

molar mass of gold=197g/mol

$mole= \tfrac{mass}{molar mass}\\ mole=\frac{591}{197}\\ mole= 3\\ Total number of atoms= mole* 6*10^{23}\\ Atoms=3*6*10^{23}\\ Total number of atoms= 18*10^{23}$