I believe it’s conductivity
Molar mass Li2O = 7.0 x 2 + 16 => 30 g/mol
1 mole Li2O ---------- 30 g
( moles Li2O ) -------- 45.0 g
moles Li2O = 45.0 x 1 / 30
moles Li2O = 45.0 / 30
= 1.50 moles of Li2O
hope this helps!
Percent composition by mass is calculated (mass of element within compound)/(mass of compound)*100. The lower the total molar mass of the compound, the greater the percent composition of sulfur. In this case, MgS would be that compound, since Mg has the lowest molar mass of the four elements bonded to S.
