How many atoms of Ag are in 0.75grams of Ag2S?

Answer 1

Molar mass Ag2S = 247.8 g/mol

moles Ag2S = 0.75 / 247.8 = 0.00303

moles Ag+ = 2 x 0.00303 = 0.00606

1 : 6.02 x 10^23 = 0.00606 : x

x = 3.65 x 10^21 atoms of Ag+

Answer 2

Ag atomic weight: 108amu = 108grams per mole
S atomic weight: 32amu = 32grams per mole

Total = 248 grams per mole of Ag2S

So you have 0.75/248 = 0.003 moles of Ag2S

That's 0.006 moles of Ag:

So it's 0.006 x (6.02 x 10^23) = [3.61 x 10^21 Ag atoms]

Answer 3

3.7 x 10^21