1. Determine the molar mass of silver (Ag). The molar mass of Ag is 107.868 g/mol.
2. Calculate the number of moles of Ag in 20.5 g.
Number of moles = mass / molar mass
= 20.5 g / 107.868 g/mol
= 0.1898 mol
3. Use Avogadro's number to determine the number of atoms in 0.1898 mol of Ag. Avogadro's number is 6.022 x 10^23 atoms/mol.
Number of atoms = number of moles × Avogadro's number
= 0.1898 mol × 6.022 x 10^23 atoms/mol
= 1.143 x 10^23 atoms
Therefore, there are approximately 1.143 x 10^23 atoms in 20.5 g of silver.
