8.
MgSO4*7H2O , miu =120+126 = 246 g/mol
246 g cristalo.............. 120 g MgSO4 ............. 126 g apa
49,2 g ............................. a g MgSO4 .................. b g apa
a = 24 g MgSO4 , b = 25,2 g apa
=> ms = 24 + 25,2 + 150,8 = 200 g
md = 22,54
c% = mdx100/ms = 24x100/200 = 12% => b)
9.
BaCl2 , c)
BaCl2 + H2SO4 => BaSO4↓ + HCl
10.
H2SO4 = 98 g/mol
5 moli x 98 = 490 g H2SO4
98 g H2SO4 ...... 32 g S
490 g H2SO4 ....... a = 160 g S => d)
