Help me

Đáp án:

a, 

$\%m_{Cl(MCl_x)}=\dfrac{35,5x}{M_M+35,5x}$ 

$\%m_{Cl(MCl_y)}=\dfrac{35,5y}{M_M+35,5y}$ 

$\Rightarrow \dfrac{y(M_M+35,5x)}{x(M_M+35,5y)}=1,173$ 

$\Rightarrow 1,173xM_M+1,173x.35,5y=yM_M+35,5xy$ 

$\Rightarrow 6,1415xy=M_M(y-1,173x)$ 

$\%m_{O(MO_{0,5x})}=\dfrac{16.0,5x}{M_M+16.0,5x}=\dfrac{8x}{M_M+8x}$ 

$\%m_{O(M_2O_y)}=\dfrac{16y}{2M_M+16y}$ 

$\Rightarrow \dfrac{2y(M_M+8x)}{x(2M_M+16y)}=1,352$ 

$\Rightarrow 1,352x(2M_M+16y)=2y(M_M+8x)$ 

$\Rightarrow 5,632xy=2M_M(y-1,352x)$ 

$\Rightarrow \dfrac{6,1415}{5,632}=\dfrac{y-1,173x}{2(y-1,352x)}$  

$\Rightarrow 1,09(y-1,173x)=2y-1,352x.2$ 

$\Rightarrow \dfrac{x}{y}=0,64\approx \dfrac{2}{3}$ 

$\Rightarrow x=2; y=3$ 

$\Rightarrow M_M=\dfrac{6,1415.2.3}{3-1,173.2}=56 g/mol$ 

b,

$M$ là $Fe$ nên có $Z=26$ 

$\dfrac{Z}{N}=\dfrac{13}{15}=\dfrac{26}{30}\Rightarrow N=30$ 

$\Rightarrow A=Z+N=26+30=56$ 

Vậy đồng vị phù hợp là $^{56}M$