Cho 11,2 gam Fe phản ứng vừa đủ với 200g dung dịch HCl
a) Tính C% của dd HCl đã dùng
b)Tính thể tích H2 ở đkc
c) Tính C% của nước trong dd sau phản ứng
*ai giúp minh với, mình cần gấp*
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Bài 1:
PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
Ta có: \(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{HCl}=0,4\left(mol\right)\\n_{H_2}=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{ddHCl}=\dfrac{0,4\cdot36,5}{14,6\%}=100\left(g\right)\\V_{H_2}=0,2\cdot22,4=4,48\left(l\right)\end{matrix}\right.\)
Bài 2:
PTHH: \(2KOH+H_2SO_4\rightarrow K_2SO_4+2H_2O\)
Ta có: \(\left\{{}\begin{matrix}n_{KOH}=\dfrac{100\cdot11,2\%}{56}=0,2\left(mol\right)\\n_{H_2SO_4}=\dfrac{150\cdot9,8\%}{98}=0,15\left(mol\right)\end{matrix}\right.\)
Xét tỉ lệ: \(\dfrac{0,2}{2}< \dfrac{0,15}{1}\) \(\Rightarrow\) H2SO4 còn dư, KOH p/ứ hết
\(\Rightarrow\left\{{}\begin{matrix}n_{K_2SO_4}=0,1\left(mol\right)\\n_{H_2SO_4\left(dư\right)}=0,05\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{K_2SO_4}=0,1\cdot174=17,4\left(g\right)\\m_{H_2SO_4\left(dư\right)}=0,05\cdot98=4,9\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd}=m_{ddKOH}+m_{ddH_2SO_4}=250\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{K_2SO_4}=\dfrac{17,4}{250}\cdot100\%=6,96\%\\C\%_{H_2SO_4\left(dư\right)}=\dfrac{4,9}{250}\cdot100\%=1,96\%\end{matrix}\right.\)
\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)
a.
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
\(V_{H_2}=24,79.0,2=4,958\left(l\right)\)
b.
\(n_{HCl}=2.n_{Fe}=0,4\left(mol\right)\\ CM_{HCl}=\dfrac{0,4}{0,2}=2M\)
\(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\\
pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\)
0,1 0,2 0,1 0,1
\(m_{HCl}=0,2.36,5=7,3\left(g\right)\\
V_{H_2}=0,1.22,4=2,24l\\
m_{\text{dd}}=6,5+200-\left(0,1.2\right)=206,3g\)
bài 2 :
\(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\\
pthh:Mg+2HCl\rightarrow MgCl_2+H_2\)
0,2 0,4 0,2 0,2
\(m_{HCl}=0,4.36,5=14,6g\\
V_{H_2}=0,2.22,4=4,48l\\
m\text{dd}=4,8+200-0,4=204,4g\\
C\%=\dfrac{0,2.136}{204,4}.100\%=13,3\%\)
\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\ PTHH:Zn+2HCl\rightarrow ZnCl_2+H_2\\ n_{H_2}=n_{ZnCl_2}=n_{Zn}=0,2\left(mol\right)\\ a,V_{H_2\left(Đktc\right)}=0,2.22,4=4,48\left(l\right)\\ b,m_{ZnCl_2}=136.0,2=27,2\left(g\right)\\ c,n_{HCl}=0,2.2=0,4\left(mol\right)\\ C\%_{ddHCl}=\dfrac{0,4.36,5}{200}.100\%=7,3\%\)
PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
a) Ta có: \(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)=n_{H_2}\) \(\Rightarrow V_{H_2}=0,2\cdot22,4=4,48\left(l\right)\)
b) Theo PTHH: \(n_{HCl}=2n_{Fe}=0,4\left(mol\right)\)
\(\Rightarrow C\%_{HCl}=\dfrac{0,4\cdot36,5}{200}\cdot100\%=7,3\%\)
b) Theo PTHH: \(n_{FeCl_2}=n_{H_2}=0,2\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}m_{FeCl_2}=0,2\cdot127=25,4\left(g\right)\\m_{H_2}=0,2\cdot2=0,4\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd}=m_{Fe}+m_{ddHCl}-m_{H_2}=210,8\left(g\right)\)
\(\Rightarrow C\%_{FeCl_2}=\dfrac{25,4}{210,8}\cdot100\%\approx12,05\%\)
a) \(n_{Fe}=\dfrac{2,8}{56}=0,05\left(mol\right)\)
PTHH: `Fe + 2HCl -> FeCl_2 + H_2`
0,05->0,1----->0,05---->0,05
`=> V_{ddHCl} = (0,1)/2 = 0,05 (l)`
b) `V_{H_2} = 0,05.22,4 = 1,12 (l)`
c) `C_{M(FeCl_2)} = (0,05)/(0,05) = 1M`
\(n_{Zn}=\dfrac{13}{65}=0,2\left(mol\right)\\
pthh:Zn+2HCl\rightarrow ZnCl_2+H_2\)
0,2 0,4 0,2
\(V_{H_2}=0,2.22,4=4,48\left(l\right)\\
C\%_{HCl}=\dfrac{0,4.36,5}{200}.100\%=7,3\%\)
\(a,n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\\ PTHH:Fe+2HCl\rightarrow FeCl_2+H_2\\ \Rightarrow n_{HCl}=0,4\left(mol\right)\\ \Rightarrow m_{CT_{HCl}}=0,4\cdot36,5=14,6\left(g\right)\\ \Rightarrow C\%_{HCl}=\dfrac{14,6}{200}\cdot100\%=7,3\%\\ b,n_{H_2}=0,2\left(mol\right)\\ \Rightarrow V_{H_2\left(đkc\right)}=0,2\cdot24,79=4,958\left(l\right)\\ c,m_{H_2}=0,2\cdot2=0,4\left(g\right)\\ n_{FeCl_2}=0,2\left(mol\right)\\ \Rightarrow m_{CT_{FeCl_2}}=0,2\cdot127=25,4\left(g\right)\\ \Rightarrow m_{dd_{FeCl_2}}=11,2+200-0,4=210,8\left(g\right)\\ \Rightarrow C\%_{FeCl_2}=\dfrac{25,4}{210,8}\cdot100\%\approx12,05\%\)