Em tham khảo nha:
\(\begin{array}{l}
a)\\
{A_{Fe}} = 0,4 \times 6 \times {10^{23}} = 2,4 \times {10^{23}}\\
b)\\
{A_{Ag}} = 0,25 \times 6 \times {10^{23}} = 1,5 \times {10^{23}}\\
c)\\
{A_{Hg}} = 0,125 \times 6 \times {10^{23}} = 7,5 \times {10^{22}}\\
d)\\
{A_{C{O_2}}} = 1,25 \times 6 \times {10^{23}} = 7,5 \times {10^{23}}\\
h)\\
{A_{Cu}} = 2,5 \times 6 \times {10^{23}} = 1,5 \times {10^{24}}\\
i)\\
{A_{Al}} = 1,25 \times 6 \times {10^{23}} = 7,5 \times {10^{23}}\\
k)\\
{A_{{O_2}}} = 0,2 \times 6 \times {10^{23}} = 1,2 \times {10^{23}}\\
l)\\
{A_{{N_2}}} = 0,5 \times 6 \times {10^{23}} = 3 \times {10^{23}}
\end{array}\)