Part A
The molar mass of silver = 107.87 g/mol ( from periodic table)
part B
The moles of silver is 0.2946 moles
calculation
moles =mass÷ molar mass
= 31.78 g ÷ 107.87 =0.2946 moles
part c
The number of atoms of silver that are in this sample is 1.773 x 10²³ atoms
calculation
According to Avogadro's law 1 mole = 6.02 x 10²³ atoms
0.2946 moles= ? atoms
by cross multiplication
= [ (0.2946 moles x 6.02 x 10²³ ) / 1 mole] = 1.773 x 10²³ atoms