\(\begin{array}{l}
a)\\
C + {O_2} \to C{O_2}\\
nC = \dfrac{3}{{12}} = 0,25\,mol\\
n{O_2} = nC = 0,25\,mol\\
m{O_2} = 0,25 \times 32 = 8g\\
V{O_2} = 0,25 \times 22,4 = 5,6l\\
b)\\
2{C_4}{H_{10}} + 13{O_2} \to 8C{O_2} + 10{H_2}O\\
n{C_4}{H_{10}} = \dfrac{{11,2}}{{22,4}} = 0,5\,mol\\
n{O_2} = 0,5 \times 6,5 = 3,25\,mol\\
m{O_2} = 3,25 \times 32 = 104g\\
V{O_2} = 3,25 \times 22,4 = 72,8l\\
c)\\
2CO + {O_2} \to 2C{O_2}\\
nC = \dfrac{{14}}{{28}} = 0,5\,mol\\
n{O_2} = 0,25\,mol\\
m{O_2} = 0,25 \times 32 = 8g\\
V{O_2} = 0,25 \times 22,4 = 5,6l\\
d)\\
4Al + 3{O_2} \to 2A{l_2}{O_3}\\
nAl = \dfrac{{6,75}}{{27}} = 0,25\,mol\\
n{O_2} = 0,1875\\
m{O_2} = 0,1875 \times 32 = 6g\\
V{O_2} = 0,1875 \times 22,4 = 4,2l
\end{array}\)
