Đặt :
nFe = x mol
nAl = y mol
Fe + 2HCl --> FeCl2 + H2
x____________x______x
2Al + 6HCl --> 2AlCl3 + 3H2
y______________y______1.5y
mhh= 56x + 27y = 5.5 g (1)
nH2 = x + 1.5y = 0.2 (2)
Giải (1) và (2) :
x = 0.05
y= 0.1
mFe = 2.8 g
mAl = 2.7 g
%Fe = 50.91%
%Al = 49.09%
Từ PTHH ta thấy :
nHCl = 2nH2 = 0.2*2=0.4 mol
mHCl = 0.4*36.5 = 14.6 g
mddHCl = 14.6*100/14.6 = 100g
mdd sau phản ứng = 5.5 + 100 - 0.4 = 105.1 g
mFeCl2 = 6.35g
mAlCl3 = 13.35g
C%FeCl2 = 6.04%
%AlCl3 = 12.7%
Fe + 2HCl → FeCl2 + H2 (1)
2Al + 6HCl → 2AlCl3 + 3H2 (2)
\(n_{H_2}=\frac{4,48}{22,4}=0,2\left(mol\right)\)
a) Gọi x,y lần lượt là số mol của Fe và Al
Ta có: \(56x+27y=5,5\) (*)
Theo Pt1: \(n_{H_2}=n_{Fe}=x\left(mol\right)\)
Theo PT2: \(n_{H_2}=\frac{3}{2}n_{Al}=1,5y\left(mol\right)\)
Ta có: \(x+1,5y=0,2\) (**)
Từ (*)(**) ta có: \(\left\{{}\begin{matrix}56x+27y=5,5\\x+1,5y=0,2\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,05\\y=0,1\end{matrix}\right.\)
Vậy \(n_{Fe}=0,05\left(mol\right)\Rightarrow m_{Fe}=0,05\times56=2,8\left(g\right)\)
\(n_{Al}=0,1\left(mol\right)\Rightarrow m_{Al}=0,1\times27=2,7\left(g\right)\)
\(\%m_{Fe}=\frac{2,8}{5,5}\times100\%=50,91\%\)
\(\%m_{Al}=100\%-50,91\%=49,09\%\)
b) Theo Pt1: \(n_{HCl}=2n_{Fe}=2\times0,05=0,1\left(mol\right)\)
Theo Pt2: \(n_{HCl}=3n_{Al}=3\times0,1=0,3\left(mol\right)\)
\(\Rightarrow\Sigma n_{HCl}=0,1+0,3=0,4\left(mol\right)\)
\(\Rightarrow\Sigma m_{HCl}=0,4\times36,5=14,6\left(g\right)\)
\(\Rightarrow m_{ddHCl}=\frac{14,6}{14,6\%}=100\left(g\right)\)
c) \(m_{H_2}=0,2\times2=0,4\left(g\right)\)
Ta có: \(m_{dd}saupứ=5,5+100-0,4=105,1\left(g\right)\)
Theo Pt1: \(n_{FeCl_2}=n_{Fe}=0,05\left(mol\right)\)
\(\Rightarrow m_{FeCl_2}=0,05\times127=6,35\left(g\right)\)
\(\Rightarrow C\%_{FeCl_2}=\frac{6,35}{105,1}\times100\%=6,04\%\)
Theo Pt2: \(n_{AlCl_3}=n_{Al}=0,1\left(mol\right)\)
\(\Rightarrow m_{AlCl_3}=0,1\times133,5=13,35\left(g\right)\)
\(\Rightarrow C\%_{AlCl_3}=\frac{13,35}{105,1}\times100\%=12,7\%\)
