nr moli=m/masa molara acid =>masa = 2*98=196 g acid sulfuric
ms = md+m apa = 196+294=490 g solutie
a)c%=md/ms*100=196/490*100=40%
b)H2SO4 + Mg ---> MgSO4 + H2
98 g H2SO4........2 g H2 98 g H2SO4......22,4 l H2
196 g H2SO4...........x g H2 196 g H2SO4...........y l H2
x = 4 g H2 = 2 moli H2 y = 44,8 litri H2 (asta in cazul in care iti trebuie)
c)98 g H2SO4..........24 g Mg
196 g H2SO4.........z g Mg z = 48 g Mg
puritatea = masa pura Mg/masa impura magneziu => masa pura Mg=90*48/100 = 43.2 g
