a)
Ta có:
\({M_{{P_2}{O_5}}} = 2{M_P} + 5{M_O} = 31.2 + 16.5 = 142{\text{ (u)}}\)
\( \to \% {m_P} = \frac{{31.2}}{{142}} = 43,66\% \)
\( \to \% {m_O} = 56,34\% \)
b)
Ta có:
\({M_{{C_{12}}{H_{22}}{O_{11}}}} = 12{M_C} + 22{M_H} + 11{M_O} = 12.12 + 22.1 + 16.11 = 342{\text{ (u)}}\)
\( \to \% {m_C} = \frac{{12.12}}{{342}} = 42,1\% \)
\(\% {m_H} = \frac{{22}}{{342}} = 6,43\% \)
\( \to \% {m_O} = 51,47\% \)