md=75 g CuSO4 anhidru
160 g..............250g cristalohidrat
75g..................x
x=117,1875g
b)CuSO4+6NH3+H20=[Cu(NH3)4](OH)2+(NH4)2SO4
160g........6.17g
75g.............md
md=47,8125g
ms=md.100/c=281,25g
c)md=c.ms/100=0,4g BaCl2
BaCl2+SO4²=BaSO4+2Cl
208 g.........1mol
0,4g..............x
x=0,00192moli