Hòa tan 21,4 g Al, Fe, Mg bằng dung dịch axit sunfuric vừa đủ thu được dung dịch A. Lượng khí H2 tạo thành dẫn vào ống sứ đựng CuO dư nung nóng. Sau phản ứng, khối lượng ống sứ giảm 11,2 g. Cô cạn dung dịch A thu được m (g) muối. Tính m.

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Giải thích các bước giải:

 CuO + `H_2`  $\xrightarrow{t°}$Cu + `H_2O`

`m_{CuO}` giảm do `m_O` thoát ra 

`n_{O}` = $\frac{11,2}{16}$ = 0,7 mol 

→`n_{H_2O}` = 0,7 mol 

Theo phương trình 

`n_{H_2}` = `n_{H_2O}` = 0,7 mol 

Bảo toàn H 

`n_{H_2SO_4}` = `n_{H_2}` = 0,7 mol 

→ `n_{SO_4}` = 0,7 mol 

`m` muối = `m` kim loại + `m_{SO_4}`

                 = 21,4 + 0,7 . 96 = 88,6g

Chúc bạn học tốt #aura

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