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a) Gọi số mol Ca, CaCO3 là a, b (mol)
=> 40a + 100b = 19 (1)
\(m_{HCl}=\dfrac{500.4,38}{100}=21,9\left(g\right)\)
PTHH: Ca + 2HCl --> CaCl2 + H2
a--->2a------->a----->a
CaCO3 + 2HCl --> CaCl2 + CO2 + H2O
b------>2b------>b------>b
=> \(\overline{M}_Y=\dfrac{2a+44b}{a+b}=13,6.2=27,2\left(g/mol\right)\)
=> 25,2a = 16,8b (2)
(1)(2) => a = 0,1 (mol); b = 0,15 (mol)
\(\left\{{}\begin{matrix}m_{Ca}=0,1.40=4\left(g\right)\\m_{CaCO_3}=0,15.100=15\left(g\right)\end{matrix}\right.\)
b)
mdd sau pư = 19 + 500 - 0,1.2 - 0,15.44 = 512,2 (g)
mHCl(dư) = 21,9 - 36,5(2a + 2b) = 3,65 (g)
mCaCl2 = 111(a + b) = 27,75 (g)
\(\left\{{}\begin{matrix}C\%_{CaCl_2}=\dfrac{27,75}{512,2}.100\%=5,418\%\\C\%_{HCl\left(dư\right)}=\dfrac{3,65}{512,2}.100\%=0,713\%\end{matrix}\right.\)
a) Gọi số mol Ca, CaCO3 là a, b (mol)
=> 40a + 100b = 19 (1)
\(m_{HCl}=\dfrac{500.4,38}{100}=21,9\left(g\right)\)
PTHH: Ca + 2HCl --> CaCl2 + H2
a--->2a------->a----->a
CaCO3 + 2HCl --> CaCl2 + CO2 + H2O
b------>2b------>b------>b
=> \(\overline{M}_Y=\dfrac{2a+44b}{a+b}=13,6.2=27,2\left(g/mol\right)\)
=> 25,2a = 16,8b (2)
(1)(2) => a = 0,1 (mol); b = 0,15 (mol)
\(\left\{{}\begin{matrix}m_{Ca}=0,1.40=4\left(g\right)\\m_{CaCO_3}=0,15.100=15\left(g\right)\end{matrix}\right.\)
b)
mdd sau pư = 19 + 500 - 0,1.2 - 0,15.44 = 512,2 (g)
mHCl(dư) = 21,9 - 36,5(2a + 2b) = 3,65 (g)
mCaCl2 = 111(a + b) = 27,75 (g)
\(\left\{{}\begin{matrix}C\%_{CaCl_2}=\dfrac{27,75}{512,2}.100\%=5,418\%\\C\%_{HCl\left(dư\right)}=\dfrac{3,65}{512,2}.100\%=0,713\%\end{matrix}\right.\)
\(a,Đặt:n_{Mg}=g\left(mol\right);n_{Fe}=j\left(mol\right)\left(g,j>0\right)\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ Mg+2HCl\rightarrow MgCl_2+H_2\\ \Rightarrow\left\{{}\begin{matrix}24g=56j=9,2\\22,4g+22,4j=5,6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}g=0,15\\j=0,1\end{matrix}\right.\\ \Rightarrow\%m_{Mg}=\dfrac{0,15.24}{9,2}.100\approx39,13\%\\ \Rightarrow\%m_{Fe}\approx60,87\%\\ b,n_{HCl}=2n_{H_2}=\dfrac{2.5,6}{22,4}=0,5\left(mol\right)\\ \Rightarrow C_{MddHCl}=\dfrac{0,5}{0,2}=2,5\left(M\right)\\ c,m_{muối}=m_{FeCl_2}+m_{MgCl_2}=95g+127j=95.0,15+127.0,1=26,95\left(g\right)\)
Fe+2HCl->FeCl2+H2
x-----------------------x mol
Mg+2HCl->MgCl2+H2
y-------------------------y mol
ta có\(\left\{{}\begin{matrix}56x+24y=9,2\\x+y=0,25\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x=0,1\\y=0,15\end{matrix}\right.\)
=>%mFe=\(\dfrac{0,1.56}{9,2}.100\)=60,87%
=>%m Mg=39,13%
Ta có : n HCl=0,1.2+0,15.2=0,5 mol
=>CMHCl=\(\dfrac{0,5}{0,2}\)=2,5M
=>m muối =0,1.127+0,15.95=26,95g
Gọi x và y lần lượt là số mol Fe và Al tham gia phản ứng
a/PTHH: Fe + H2SO4 -----> FeSO4 + H2
(mol) x x x x
PTHH: 2Al + 3H2SO4 -----> Al2(SO4)3 + 3H2
(mol) y 3y/2 y/2 3y/2
Suy ra hệ : \(\begin{cases}152x+\frac{342y}{2}=81,7\\56x+27y=19,3\end{cases}\) \(\Leftrightarrow\begin{cases}x=0,2\\y=0,3\end{cases}\)
=> mFe = 0,2.56 = 11,2 (g)
\(\Rightarrow\%Fe=\frac{11,2}{19,3}.100\approx58,03\%\)
%Al = 100% - 58,03% = 41,97%
b/ nH2 = x+3y/2 = 0,2 + 3.0,3/2 = 0,65 (mol)
=> VH2 = 22,4.0,65 = 14,56 (l)
c/ nH2SO4 = x+3y/2 = 0,65 (mol)
=> mH2SO4 = 98.0,65 = 63,7 (g)
\(n_{H_2}=\dfrac{4,47}{22,4}\approx0,21\left(mol\right)\\ PTHH:\\ 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\uparrow\\ Mg+H_2SO_4\rightarrow MgSO_4+H_2\uparrow\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)
Theo các pthh:
\(n_{H_2SO_4}=n_{H_2}=0,21\left(mol\right)\\ \rightarrow m_{H_2SO_4}=0,21.98=20,58\left(g\right)\\ \rightarrow m_{ddH_2SO_4}=\dfrac{20,58}{9,8\%}=210\left(g\right)\\ m_{H_2}=0,21.2=0,42\left(g\right)\\ \rightarrow m_{dd\left(sau\right)}=210+4,46-0,42=214,04\left(g\right)\)