Em tham khảo nha :
\(\begin{array}{l}
B1:\\
1)\\
{n_{Fe}} = \dfrac{{8,4}}{{56}} = 0,15mol\\
2)\\
{n_{{O_2}}} = \dfrac{8}{{32}} = 0,25mol\\
{V_{{O_2}}} = 0,25 \times 22,4 = 5,6l\\
3)\\
{n_{{N_2}}} = \dfrac{{67,2}}{{22,4}} = 3mol\\
{m_{{N_2}}} = 3 \times 28 = 84g\\
4)\\
{n_{Ca}} = \dfrac{{4,5 \times {{10}^{23}}}}{{6 \times {{10}^{23}}}} = 0,75mol\\
{m_{Ca}} = 0,75 \times 40 = 30g\\
B2:\\
1)\\
{n_{Cu}} = \dfrac{{0,96}}{{64}} = 0,015mol\\
2)\\
{n_{Ba}} = \dfrac{{30,14}}{{137}} = 0,22mol\\
3)\\
{n_{CaO}} = \dfrac{{70}}{{56}} = 1,25mol\\
4)\\
{n_{N{H_3}}} = \dfrac{{6,12}}{{17}} = 0,36mol\\
5)\\
{n_{BaC{O_3}}} = \dfrac{{76,83}}{{197}} = 0,39mol\\
6)\\
{n_{N{H_3}}} = \dfrac{{8,064}}{{22,4}} = 0,36mol\\
B3:\\
1)\\
{V_{{H_2}}} = 0,105 \times 22,4 = 2,352l\\
2)\\
{V_{{N_2}}} = 2,24 \times 22,4 = 50,176l\\
3)\\
{n_{N{O_2}}} = \dfrac{{3,68}}{{46}} = 0,08mol\\
{V_{N{O_2}}} = 0,08 \times 22,4 = 1,792l
\end{array}\)