Em tham khảo nha:

\(\begin{array}{l}
a)\\
Cu:\\
M = 64g/mol\\
n = 0,3\,mol\\
m = n \times M = 0,3 \times 64 = 19,2g\\
{H_2}:\\
M = 2g/mol\\
n = \dfrac{m}{M} = \dfrac{4}{2} = 2\,mol\\
m = 4g\\
V = n \times 22,4 = 2 \times 22,4 = 44,8l\\
{N_2}:\\
M = 28g/mol\\
n = \dfrac{V}{{22,4}} = \dfrac{{11,2}}{{22,4}} = 0,5\,mol\\
m = n \times M = 0,5 \times 28 = 14g\\
V = 11,2l\\
C{O_2}:\\
M = 44g/mol\\
n = 0,15\,mol\\
m = n \times M = 0,15 \times 44 = 6,6g\\
V = n \times 22,4 = 0,15 \times 22,4 = 3,36l\\
{H_2}S{O_4}:\\
M = 98g/mol\\
n = 0,8\,mol\\
m = n \times M = 0,8 \times 98 = 78,4g\\
{C_6}{H_6}:\\
M = 78g/mol\\
n = \dfrac{m}{M} = \dfrac{{62,4}}{{78}} = 0,8\,mol\\
m = 62,4g\\
KMn{O_4}:\\
M = 158g/mol\\
n = \dfrac{m}{M} = \dfrac{{15,8}}{{158}} = 0,1\,mol\\
m = 15,8g\\
b)\\
{n_{{C_2}{H_2}}} = \dfrac{N}{{6 \times {{10}^{23}}}} = \dfrac{{7,5 \times {{10}^{30}}}}{{6 \times {{10}^{23}}}} = 12500000\,mol\\
{m_{{C_2}{H_2}}} = 12500000 \times 26 = 325000000g = 325\text{ tấn}\\
{V_{{C_2}{H_2}}} = 12500000 \times 22,4 = 280000000l = 280000{m^3}
\end{array}\)