Em tham khảo nha:

2)

\(\begin{array}{l}
a)\\
CTHH:X{Y_2}\\
MX{Y_2} = 22 \times 2 = 44g/mol\\
b)\\
MX + 2MY = 44(1)\\
\dfrac{{mX}}{{mY}} = \dfrac{3}{8} \Rightarrow \dfrac{{MX}}{{2MY}} = \dfrac{3}{8} \Rightarrow 4MX = 3MY(2)\\
(1),(2) \Rightarrow MX = 12;MY = 16\\
 \Rightarrow X:Cacbon(C),Y:Oxi(O)\\
 \Rightarrow CTHH:C{O_2}\\
3)\\
a)\\
CTHH:X{Y_3}\\
MX{Y_3} = MBr = 80g/mol\\
b)\\
MX + 3MY = 80(1)\\
\dfrac{{mX}}{{mY}} = \dfrac{2}{3} \Rightarrow \dfrac{{MX}}{{3MY}} = \dfrac{2}{3} \Rightarrow MX = 2MY(2)\\
(1),(2) \Rightarrow MX = 32;MY = 16\\
 \Rightarrow X:S\,;Y:O
\end{array}\)