can someone please help me on the second one? I have no idea what to do.

The reaction will produce 12.1 g Ag₂S.
Balanced equation = 2Ag + S ⟶ Ag₂S
Mass of Ag₂S = 10.5 g Ag × (1 mol Ag/107.87 g Ag) × (1 mol Ag₂S/2 mol Ag)
× (247.80 g Ag₂S/1 mol Ag₂S) = 12.1 g Ag₂S