+2 -1
13 В Са(NO3)2 = Ca + 2NO3
14. Д S 1 s2 2s2 2p6 3s2 3p4
0 0 +1 -2
15 Д 4Аg + O2 = Ag2O
16 B 3мольNaCI = 3x58.5 = 175.5 10моль Н2О =180 180+175,5=355,5
w% = 175.5 / 355.5 x100 = 49.4
17 A Mr (CH4) = 16 w% = 4 / 16 x100=25%
18 D D(O2) = Mr(CI2) / Mr(O2) = 71 / 32 = 2.22