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Answer 1

Câu 13:

\(n_{Fe}=\dfrac{2,8}{56}=0,05\left(mol\right)\\ n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\\ n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ Zn+H_2SO_4\rightarrow ZnSO_4+H_2\\ Mg+H_2SO_4\rightarrow MgSO_4+H_2\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ Mg+2HCl\rightarrow MgCl_2+H_2\\ Zn+2HCl\rightarrow ZnCl_2+H_2\\ \Rightarrow n_{H_2}=n_{Mg}+n_{Zn}+n_{Fe}=0,1+0,1+0,05=0,25\left(mol\right)\\ V=V_{H_2\left(đktc\right)}=0,25.22,4=5,6\left(lít\right)\)

Answer 2

Câu 14:

\(Đặt:x.là.hoá.trị.R\left(a:nguyên,dương\right)\\ 4R+xO_2\rightarrow\left(t^o\right)2R_2O_x\\ n_R=\dfrac{0,1.4}{x}=\dfrac{0,4}{x}\left(mol\right)\\ M_R=\dfrac{14,4}{\dfrac{0,4}{x}}=36x\left(\dfrac{g}{mol}\right)\\ \)

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