1)
Phản ứng xảy ra:
\(X + {F_2}\xrightarrow{{{t^o}}}X{F_2}\)
Ta có:
\({n_{{F_2}}} = \frac{{1,792}}{{22,4}} = 0,08{\text{ mol = }}{{\text{n}}_X}\)
\( \to {M_X} = \frac{{1,92}}{{0,08}} = 24\)
\( \to X:Mg\) (magie)
2)
Gọi \(n\) là hóa trị của \(M\)
Phản ứng xảy ra:
\(2M + n{X_2}\xrightarrow{{{t^o}}}2M{X_n}\)
Ta có:
\({n_{B{r_2}}} = \frac{{12}}{{80.2}} = 0,075{\text{ mol}}\)
\( \to {n_M} = \frac{{2{n_{B{r_2}}}}}{n} = \frac{{0,075.2}}{n} = \frac{{0,15}}{n}\)
\( \to {M_M} = \frac{{1,35}}{{\frac{{0,15}}{n}}} = 9n\)
Thỏa mãn \(n=3 \to M_M=27 \to M:Al\) (nhôm)
3)
Gọi \(n\) là hóa trị của \(M\)
Phản ứng xảy ra:
\(2M + n{F_2}\xrightarrow{{{t^o}}}2M{F_n}\)
BTKL:
\({m_M} + {m_{{F_2}}} = {m_{M{F_n}}}\)
\( \to 11,2 + {m_{{F_2}}} = 22,6{\text{ }} \to {{\text{m}}_{{F_2}}} = 11,4{\text{ gam}}\)
\( \to {n_{{F_2}}} = \frac{{11,4}}{{19.2}} = 0,3{\text{ mol}}\)
\( \to {n_M} = \frac{{2{n_{{H_2}}}}}{n} = \frac{{0,6}}{n}\)
\( \to {M_M} = \frac{{11,2}}{{\frac{{0,6}}{n}}} = \frac{{56n}}{3}\)
Thỏa mãn \(n=3 \to M_M=56 \to M:Fe\) (sắt)
4)
Phản ứng xảy ra:
\(Mg + {X_2}\xrightarrow{{{t^o}}}Mg{X_2}\)
Ta có:
\({n_{Mg}} = \frac{{19,2}}{{24}} = 0,8{\text{ mol = }}{{\text{n}}_{Mg{X_2}}}\)
\( \to {M_{Mg{X_2}}} = \frac{{222,4}}{{0,8}} = 278 = {M_{Mg}} + 2{M_X} = 24 + 2{M_X}\)
\( \to M_X=127 \to X:I\) (iot)