Cần gấp ạ.

Em tham khảo nha:

$\begin{array}{l} a)\,N{a_2}S:PTK = 23 \times 2 + 32 = 78\,dvC\\ b)\,FeC{l_3}:PTK = 56 + 35,5 \times 3 = 162,5\,dvC\\ c)\,Cu{(N{O_3})_2}:PTK = 64 + 14 \times 2 + 16 \times 6 = 188\,dvC\\ d)\,{P_2}{O_5}:PTK = 31 \times 2 + 16 \times 5 = 142\,dvC\\ e)\,A{l_2}{S_3}:PTK = 27 \times 2 + 32 \times 3 = 150\,dvC\\ f)Al{(N{O_3})_3}:PTK = 27 + 14 \times 3 + 16 \times 9 = 213\,dvC \end{array}$