S(0) -4е -> S(+4). |4. |1
O2(0) +4e -> 2O (-2). |4. |1
S+O2 = SO2 так и останется
5) Mr(Zn(OH)2) = 65 + 16*2 + 1*2 = 99
6) W(O) = Ar(O) *n / Mr(Na2O) *100% = 16 *1 / 62 *100% = 25,8 %
W(O) = Ar(O) * n / Mr(Al2O3) *100% =16 * 3 / 102 *100% =47%
M(CnH2n) = D (N2) * m(N2) = 3,5 * 28 = 98.
14n = 98. n = 7, C7H14 - гексен