Answer :
Molar mass MgS2O3 = 136.43 g/mol
Therefore:
1 mole MgS2O3 ---------- 136.43 g
? moles MgS2O3 ------- 163 g
moles MgS2O3 = 163 x 1 / 136.43
moles MgS2O3 = 163 / 136.43 => 1.1947 moles
Therefore:
1 mole MgS2O3 ---------- 136.43 g
? moles MgS2O3 ------- 163 g
moles MgS2O3 = 163 x 1 / 136.43
moles MgS2O3 = 163 / 136.43 => 1.1947 moles