Ответ:
4)
K2MnO4
M(K2MnO4) = 39*2+55+16*4 = 197 g/mol
W(K) = 39*2 / 197 * 100% = 39.6%
W(Mn) = 55 / 197 * 100% = 27.9 %
W(O) = 100% - (39.6% +27.9%) = 32,5%
CaSO4
M(CaSO4) = 136 g/mol
W(Ca) = 40 / 136 * 100% = 29.4%
W(S) = 32 / 136 * 100% = 23.53%
W(O) = 100% - ( 29.4% + 23.53%) = 47.07 %
Cu(OH)2
M(Cu(OH)2) = 64 + 16*2+1*2 = 98 g/mol
W(Cu) = 64 / 98 * 100% = 65.31 %
W(O) = 16 * 2 / 98 *100% = 32.65%
W(H) = 1*2 / 98*100% = 2.04
Zn+Br2-->ZnBr2
3Ca+2P-->Ca3P2
4Fe+3O2-->2Fe2O3
Ca+S-->CaS
2P+5CL2-->2PCL5
2Na+S-->Na2S
2HCL+Mg-->MgCL2+H2
N2+3H2-->2NH3
2H2O-->2H2+O2
Объяснение: