Răspuns:
1.
1.2 K+Cl2=2KCl
2. 2Mg+O2=2MgO
3. 2Al+3C12=2AlCl3
4. 2Cu+02=2CuO
5. H2+Cl2=2HCl
6. 2H2+02=2H2O
7. S+02=SO2
8. C+02=CO2
2.
4Na+ O2=>2 Na2O
MNa=23g/mol
MO2=2×16=32g/mol
MNa2O=2×23+16=62g/mol
4×23+32=124g reactanti
2×62=124g produși de reactie
124g=124g
3.
MO2=2×16=32g/mol
MCaO=40+16=56g/mol
32g 2×56g
2Ca+ O2=> 2CaO
xg 56g
x= 56×32/2×56=16gO2.