Răspuns:
5.
a) 3Fe + 2O2=> Fe3O4
b) 2KClO3=> 2KCl+3O2
c) 4P+ 5O2=> 2P2O5
6.
MK=39g/mol
MKCl=39+35,5=74,5g/mol
m=2,5×39=97,5g K
2×39g......................2×74,5g
2K + Cl2 => 2KCl
97,5g...........................xg
x=97,5×2×74,5/2×39=calculează
2moli 2moli
2K + Cl2 => 2KCl
2,5moli ymoli
y= 2,5×2/2=2,5 moli KCl
7.
2Al+6HCl =>2AlCl3+ 3H2
d)13
8
a) MO2=2×16=32g/mol
MCu=64g/mol
m=64×2=128gCu
2×64g.....32g
2Cu + O2=> 2CuO
128g.........yg
y=128×32/2×64=32gO2
b)
MP=31g/mol
MO2=2×16=32g/mol
m=2×31=62gP
4×31g 5×32g
4P + 5 O2 => 2P2O5
62g zg
z=62×5×32/4×31=80gO2
