What is the formula mass of a molecule of silver sulfide if the mass number of silver is 108 and the mass number of sulfur is 32?

The formula mass of a molecule of silver sulfide (Ag2S) can be calculated by adding the atomic masses of each element in the compound. The Atomic Mass of silver (Ag) is 108 and the atomic mass of sulfur (S) is 32. For Ag2S, there are 2 atoms of silver and 1 atom of sulfur.

Therefore, the formula mass of silver sulfide (Ag2S) would be: (2 x 108) + (1 x 32) = 216 + 32 = 248 amu.