\(\begin{array}{l}
C + {O_2} \to C{O_2}\\
nC = \dfrac{{96}}{{12}} = 8\,mol\\
= > n{O_2} = 8mol\\
V{O_2} = 8 \times 22,4 = 179,2l\\
m{O_2} = 8 \times 32 = 256g\\
4P + 5{O_2} \to 2{P_2}{O_5}\\
nP = \dfrac{{7,75}}{{31}} = 0,25\,mol\\
= > n{O_2} = 0,3125\,mol\\
V{O_2} = 0,3125 \times 22,4 = 7l\\
m{O_2} = 0,3125 \times 32 = 10g
\end{array}\)