Ta có : `\frac{m_Y}{m_Z}=\frac{1}{1}`
`=> m_Y=m_Z`
`=> 2m_Y=44,8g`
`=> m_Y=m_Z=22,4g`
`=> `$\begin{cases} n_{Y}=\dfrac{22,4}{M_Y}(mol)\\ n_Z=\dfrac{22,4}{m_Z}(mol)\\\end{cases}$
Gỉa sử `M_Y> M_Z`
Ta lại có: `n_{Y}-n_{Z}=0,05(mol)`
`=> \frac{22,4}{M_Y}-\frac{22,4}{M_Z}=0,05(mol)`
`=> 22,4(\frac{1}{M_Y}-\frac{1}{M_Z})=0,05`
`=> \frac{1}{M_Y}-\frac{1}{M_Z}=\frac{1}{448}(1)`
Mặc khác:
`M_Y=M_Z+8`
`=> M_Z=M_Y-8(2)`
Thế `(2)` vào `(1)`, ta được:
`\frac{1}{M_Y}-\frac{1}{M_Y-8}=\frac{1}{448}`
`=> 448M_Y-448M_Y+3584=M_Y(M_Y-8)`
`=> (M_Y)^2-8M_Y-3584=0`
`=>(M_Y)^2+56M_Y-64M_Y-3584=0`
`=> M_Y(M_Y+56)-64(M_Y+56)=0`
`=> (M_Y+56)(M_Y-64)=0`
Do `M_Z, M_Y ∈ Z | M_Z, M_Y>0`
`=> M_Y=-56(\text{(loại})`
`=> M_Y=64 (Cu)`
Vậy `Y` là `Cu`
Ta có: `64=M_{X}+8`
`=> M_X=64-8=56(Fe)`
Vậy `X` là `Fe`
