Can someone 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

answer; ///electron cloud

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"