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a, Cu không tác dụng với dd HCl.
PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, Ta có: \(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
Theo PT: \(n_{Zn}=n_{H_2}=0,2\left(mol\right)\)
\(\Rightarrow m_{Zn}=0,2.65=13\left(g\right)\)
\(\Rightarrow m_{Cu}=19,4-13=6,4\left(g\right)\)
c, Ta có: \(\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{13}{19,4}.100\%\approx67,01\%\\\%m_{Cu}\approx32,99\%\end{matrix}\right.\)
Bạn tham khảo nhé!
a, PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
Ta có: \(n_{Zn}=n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
\(\Rightarrow m_{Zn}=0,2.65=13\left(g\right)\)
Bạn xem lại xem đề cho bao nhiêu gam hỗn hợp nhé, vì mZn đã bằng 13 (g) rồi.
a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
\(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
Theo PT: \(n_{Zn}=n_{H_2}=0,2\left(mol\right)\Rightarrow m_{Zn}=0,2.65=13\left(g\right)\)
\(\Rightarrow m_{Ag}=20-13=7\left(g\right)\)
b, \(\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{13}{20}.100\%=65\%\\\%m_{Ag}=100-65=35\%\end{matrix}\right.\)
\(n_{H_2}=\dfrac{3,36}{22,4}=0,15mol\)
\(\left\{{}\begin{matrix}n_{Al}=x\left(mol\right)\\n_{Ag}=y\left(mol\right)\end{matrix}\right.\Rightarrow27x+108y=4,2\left(1\right)\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
0,1 0,05 0,15
\(\Rightarrow m_{Al}=0,1\cdot27=2,7g\)
\(\Rightarrow m_{Ag}=4,2-2,7=1,5g\)
a)\(\%m_{Al}=\dfrac{2,7}{4,2}\cdot100\%=64,28\%\)
\(\%m_{Ag}=100\%-64,28\%=35,72\%\)
b)\(m_{muối}=0,05\cdot342=17,1g\)
a)PTHH: CuO + H2\(\rightarrow\) Cu + H2O (1)
Fe2O3 + 3H2 \(\rightarrow\)2Fe + 3H2O(2)
b) nH2= \(\dfrac{5,6}{22,4}\)=0,25mol
Gọi nH2(PT1)=a
nH2(PT2)=b
=>a+b=0,25mol
<=> a=0,25-b
Theo PT1: nCuO=nH2(PT1)=a
Theo PT2: nFe2O3=1/3nH2(PT2)=1/3b
Có mCuO+mFe2O3=16g
80a+160.1/3b=16
80(0,25-b)+160/3b=16
20-80b+160/3b=16
b=0,03mol
nFe2O3=1/3.0,15=0,03mol
mFe2O3=0,03.160=8g
%mFe2O3=\(\dfrac{8}{16}\).100%=50%
%mCuO=100%-50%=50%
c)nCuO=0,25-0,15=0,1mol
Theo PT1: nCu=nCuO=0,1mol
=>mCu=0,1.64=6,4g
Theo PT2: nFe=2nFe2O3=0,06mol
mFe=0,06.56=3,36g
PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\)
\(n_{H_2}=\dfrac{13,44}{22,4}=0,6\left(mol\right)\)
Theo PTHH: \(n_{Mg}=n_{H_2}=0,6\left(mol\right)\)
=> \(m_{Mg}=0,6.24=14,4\left(g\right)\)
=> \(m_{Cu}=50-14,4=35,6\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%Mg=\dfrac{14,4}{50}.100=28,8\%\\\%Cu=\dfrac{35,6}{50}.100=71,2\%\end{matrix}\right.\)
\(n\)H2 =\(\dfrac{13,44}{22,4}\) =0,6(mol)
PTHH:
Mg +HCl →MgCl2 + H2
0,6 mol ←0,6 mol
a) \(m\)Mg =0,6. 24 =14,4(g)
\(m\)Cu= 50- 14,4= 35,6(g)
b)\(m\)%Mg= \(\dfrac{14,4}{50}\).100%= 28,8%
\(m\)%Cu=100%- 28,8%= 71,2%
Fe + H2SO4 => FeSO4 + H2
Ag đứng sau H => ko tác dụng H2SO4
nH2 = m/M = 16/2 = 8 (mol) => nFe = 8 (mol)
mFe = n.M = 56x8 = 448 (g)
==> mAg = 500 - 448 = 52 (g)
%m Fe = 448 x 100 / 500 = 89.6 %
==> % m Ag = 100 - 89.6 = 10.4 (%)