Giải:
a, CTHH: `KCl`
PTK: `39 + 35,5 = 74,5` (đvC)
b, CTHH: `Al_2 (SO_4)_3`
PTK: `2 . 27 + (32 + 16 . 4) . 3 = 342` (đvC)
c, CTHH: `Cu(OH)_2`
PTK: `64 + (16 + 1) . 2 = 98` (đvC)
d. CTHH: `KClO_3`
PTK: `39 + 35,5 + 16 . 3 = 122,5` (đvC)
e, CTHH: `H_2 SO_3`
PTK: `1 . 2 + 32 + 16 . 3 = 82` (đvC)
f, CTHH: `P_2 O_5`
PTK: `31 . 2 + 16 . 5 = 142` (đvC)
g, CTHH: `Zn(NO_3)_2`
PTK: `65 + (14 + 16 . 3) . 2 = 189` (đvC)