MgSO4 + BaCl2 = BaSO4↓ + MgCl2
MMgSO4=AMg+AS+4AO=24+32+4*16=120g/mol
MBaSO4=ABa+AS+4AO=137+32+4*16=233g/mol
MBaCl2 = ABa+2ACl=137+2*35,5=208g/mol
208g BaCl2..........................233g BaSO4
52g BaCl2...................................xg
x=52*233/208=Calculeaza!!