Cred ca asa s ar rezolva
1) Mg+ 2HCl —> MgCl2 + H2
ms= 100g c=73%
=> md= ms*c/100= 73
M HCl= 36 g/mol
n HCl=md/M
n~2 moli HCl ce reactioneaza
=> in reactie avem:
1 mol Mg ... 2 moli HCl
=>prin regula de 3 simpla 1 mol Mg reactioneaza
=> m Mg=n*M=1*24=24g Mg
tot din reactie => 1 mol H2
n=V/Vm
Conditiile sunt normale=> V=1*Vm=22,4 L H2
=> m=n*M= 2*1=2g H2
Sper ca e corecta