M.Na2SO4x10H2O = 142+180 = 322 g/mol
md.Na2SO4 = md g
ms = m.apa + m.cristalohidrat = 250+m
w% = mdx100/ms => ms = mdx100/w%
=> 250+m = 100md/6
1500+6m = 100md => md = 15+0,06m
322g cristaloh. ...................... 142 g Na2SO4 anh.
m ............................................. 15+0,06m
=> m = 34/0,864 = 39,4 g cristalohidrat
=> md = 15+0,06m = 17,36 g Na2SO4 anh.
facem proba
ms = 250+m = 250+39,4 = 289,4 g sol
md = 17,36 g
=> w% = 17,36x100/289,4 = 6%, deci verifica calculele de mai sus
