Răspuns:
1.
a)
H2O2
r.at.H:O=2:2=1:1
r.m H:O=2:32=1:16
MH2O2 =2×1+2×16=34g/mol
b)
AlCl3
r.at. Al: Cl=1:3
r.m Al:Cl=27:106,5
MAlCl3 =27+3×35,5=133,5g/mol
c)
H3PO4
r.at H:P:O=3:1:4
r.m H:P:O=3:31:48
MH3PO4 =3×1+31+3×16=82g/mol
d)
Al(OH)2
r.at. Al: O: H=1:3:3
r.m Al:O:H=27:48:3=9:16:1
MAl(OH)3=27+3×16+3×1=78g/mol
2.
a) N2 +3H2 => 2NH3
b) 2H2O + O2 => 2H2O2
c) 4Al +3O2 => 2Al2O3
d) 2Na + 2H2O => 2NaOH + H2
e) 2 Al + 6HCl => 2AlCl3 + 3H2
f) 2KClO3 => 2KCl + 3O2
3.
MNaOH=23+16+1=40g/mol
40g NaOH.......23gNa
120gNaOH.......xg Na
x=120×23/40=calculează
