/с2н5 /сн3
сн3-сн2-сн2-сн2-сн2-сн2-сн2-сн3
/сн3
А1-3
А2-4
А3-3
А4-3
А5-<span>Na2O, MgО, СaО
А6-2
А7-2
А8-3
А9-1
А10-3
А11-2
А12-</span>2ZnS + 3O2 → 2ZnO + 2SО2 <span>S(-2) -6e- ----> S(+4) I 2 <span>O2(0) +4e- -> 2O(-2) I 3</span></span>
2/
25g xmol
Na2O+HNO3=NaNO3+H2O
63g 1mol
x=25·1/63=≈4mol
3/
12.4g xmol
Ba(NO3)2+H2SO4=BaSO4↓+2H2O
261g 1mol
x=12.4·1/261=≈0.05mol
<span>....Na2(+1)Cu2(+6)O7(-2)</span>