`@KAY`
PTPU:
`\begin{array}{l} 4P + 5{O_2} \to 2{P_2}{O_5}\\ {n_P} = 0,1mol\\ \to {n_{{O_2}}} = \dfrac{5}{4}{n_P} = 0,125mol\\ \to {V_{{O_2}}} = 2,8l\\ \to {V_{KK}} = 5{V_{{O_2}}} = 14l\\ \to {n_{{P_2}{O_5}}} = \dfrac{1}{2}{n_P} = 0,05mol \to {m_{{P_2}{O_5}}} = 7,1g \end{array}`
b)
Theo pt:
`n_{P_2O_5}=\frac{1}{2}n_{P}=0,05mol.`
`⇒m_{P_2O_5}=0,05.142=7,1g.`