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mH2O = n . M = 0,45 . 18 = 8,1 ( g )
⇒ Đáp án: B. 8,1 g
\(n_{Fe_2O_3}=\dfrac{32}{160}=0,2mol\)
\(Fe_2O_3+3H_2\rightarrow\left(t^o\right)2Fe+3H_2O\)
0,2 0,4 ( mol )
\(m_{Fe}=0,4.56=22,4g\)
=> Chọn A
\(n_{H_2}=\dfrac{11,2}{22,4}=0,5mol\)
Gọi \(\left\{{}\begin{matrix}n_{Al}=x\\n_{Mg}=y\end{matrix}\right.\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
x 3/2x
\(Mg+H_2SO_4\rightarrow MgSO_4+H_2\)
y y ( mol )
Ta có:
\(\left\{{}\begin{matrix}27x+24y=10,2\\\dfrac{3}{2}x+y=0,5\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,2\end{matrix}\right.\)
\(\Rightarrow m_{Al}=0,2.27=5,4g\)
\(\Rightarrow m_{Mg}=0,2.24=4,8g\)
=> Chọn C
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1mol\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
0,1 0,1 ( mol )
\(m_{Fe}=0,1.56=5,6g\)
\(\rightarrow m_{Cu}=10-5,6=4,4g\)
--> B
\(n_K=\dfrac{11,7}{39}=0,3\left(mol\right)\)
PT: \(2K+2H_2O\rightarrow2KOH+H_2\)
Theo PT: \(n_{KOH}=n_K=0,3\left(mol\right)\Rightarrow m_{KOH}=0,3.56=16,8\left(g\right)\)
→ Đáp án: B
\(n_{H_2}=\dfrac{5.6}{22.4}=0.25\left(mol\right)\)
\(Ba+2HCl\rightarrow BaCl_2+H_2\)
\(0.25................................0.25\)
\(m_{Ba}=0.25\cdot137=34.25\left(g\right)\)
$Ba+2HCl\to BaCl_2+H_2\uparrow$
$n_{H_2}=\dfrac{5,6}{22,4}=0,25(mol)$
Theo PT: $n_{Ba}=n_{H_2}=0,25(mol)$
$\Rightarrow m_{Ba}=0,25.137=34,25(g)$
$\to A$
\(n_{SO_2}=\dfrac{44,8}{22,4}=2\left(mol\right)=>m_{SO_2}=2.64=128\left(g\right)\)
\(n_{CO}=\dfrac{5,6}{22,4}=0,25\left(mol\right)=>m_{CO}=0,25.28=7\left(g\right)\)
=> mhh = 128 + 7 = 135 (g)
=> A
D
D