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\(n_{Fe_2O_3}=\dfrac{8}{160}=0,05\left(mol\right)\)
PTHH: Fe2O3 + 3H2SO4 --> Fe2(SO4)3 + 3H2O
______0,05------>0,15--------->0,05
=> mH2SO4 = 0,15.98 = 14,7(g)
=> \(C\%\left(H_2SO_4\right)=\dfrac{14,7}{100}.100\%=14,7\%\)
\(C\%\left(Fe_2\left(SO_4\right)_3\right)=\dfrac{0,05.400}{8+100}.100\%=18,52\%\)
PTHH: Fe2(SO4)3 + 6NaOH --> 2Fe(OH)3\(\downarrow\) + 3Na2SO4
________0,05----------------------->0,1
=> mFe(OH)3 = 0,1.107=10,7(g)
\(a,PTHH:CuCl_2+2KOH\rightarrow Cu\left(OH\right)_2+2KCl\\ ...0,2......0,4.......0,2........0,4\left(mol\right)\\ b,n_{CuCl_2}=\dfrac{27}{135}=0,2\left(mol\right)\\ m_{Cu\left(OH\right)_2}=0,2\cdot98=19,6\left(g\right)\\ c,m_{KOH}=0,4\cdot56=22,4\left(g\right)\\ m_{dd_{KOH}}=\dfrac{22,4\cdot100\%}{20\%}=112\left(g\right)\\ m_{dd_{KCl}}=m_{CuCl_2}+m_{dd_{KOH}}-m_{Cu\left(OH\right)_2}=27+112-19,6=119,4\left(g\right)\)
\(d,C\%_{dd_{KCl}}=\dfrac{74,5\cdot0,4}{119,4}\cdot100\%\approx24,96\%\)
PTHH: \(CaCl_2+Na_2CO_3\rightarrow CaCO_3\downarrow+2NaCl\)
a+b) Ta có: \(n_{CaCl_2}=0,1\cdot2=0,2\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{CaCO_3}=0,2\left(mol\right)\\n_{NaCl}=0,4\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{CaCO_3}=0,2\cdot100=20\left(g\right)\\C_{M_{NaCl}}=\dfrac{0,4}{0,1+0,2}\approx1,33\left(M\right)\end{matrix}\right.\)
c) PTHH: \(CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2\)
Theo PTHH: \(n_{HCl}=2n_{CaCO_3}=0,4\left(mol\right)\) \(\Rightarrow m_{ddHCl}=\dfrac{0,4\cdot36,5}{10\%}=146\left(g\right)\)
a.PTHH:CaCl2+Na2CO3--->CaCO3+2NaCl
Ta có:nCaCl2=0,2
=>nCaCO3=nCaCl2=0,2(mol)=>mCaCO3(kết tủa)=100.0,2=2(g)
b.Vdd=100+200=300(ml)=0,3(l)
CM Nacl=(2.0,2)/0,3=4/3(M)(Đề cho 2 chất td vừa đủ nên dd sau pứ chỉ có NaCl)
c.CaCO3+2HCl--->CaCl2+CO2+H2O
nHCl(cần dùng)=2.0.2=0,4(mol)=>mHCl=36,5.0,4=14,6(g)
=>mddHCl=14,6/10%=146(g)
a)
$AgNO_3 + HCl \to AgCl + HNO_3$
Theo PTHH :
$n_{AgCl} = n_{HCl} = n_{AgNO_3} = \dfrac{340.10\%}{170} =0,2(mol)$
$m_{dd\ HCl} = \dfrac{0,2.36,5}{7,3\%} = 100(gam)$
b)
$m_{AgCl} = 0,2.143,5 = 28,7(gam)$
c)
$m_{dd\ sau\ pư} = 340 + 100 -28,7 = 411,3(gam)$
$n_{HNO_3} = n_{AgNO_3} = 0,2(mol)$
$\Rightarrow C\%_{HNO_3} = \dfrac{0,2.63}{411,3}.100\% = 3,06\%$
PTHH: \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
Ta có: \(n_{Na_2SO_4}=n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=\dfrac{1}{2}\cdot\dfrac{10}{40}=0,125\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}m_{ddH_2SO_4}=\dfrac{0,125\cdot98}{10\%}=122,5\left(g\right)\\m_{Na_2SO_4}=0,125\cdot142=17,75\left(g\right)\end{matrix}\right.\)
\(\Rightarrow C\%_{Na_2SO_4}=\dfrac{17,75}{10+122,5}\cdot100\%\approx13,4\%\)
a) \(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
PTHH: Mg + 2HCl --> MgCl2 + H2
_____0,1<-0,2------<0,1<---0,1
=> mMgCl2 = 0,1.95 = 9,5 (g)
b) \(C_{M\left(HCl\right)}=\dfrac{0,2}{0,2}=1M\)
a) \(n_{K2SO4}=\dfrac{17,4}{174}=0,1\left(mol\right)\)
PTHH : \(K_2SO_4+BaCl_2-->BaSO_4\downarrow+2KCl\)
Theo PTHH :nBaSO4 = nK2SO4 = 0,1 (mol)
=> mBaSO4 = 0,1. 233 = 23,3 (g)
b) Theo PTHH :
nKCl = 2nK2SO4 = 0,2 (mol)
nBaCl2 = nK2SO4 = 0,1 (mol)
=> mBaCl2 = 0,1.208 = 20,8 (g)
=> m(ddBaCl2) = 20,8 : 10.100 = 208 (g)
Áp dụng định luật bảo toàn khối lượng :
mK2SO4 + m(ddBaCl2) = mBaSO4 + m(ddKCl)
=> 17,4 + 208 = 23,3 + m(ddKCl)
=> m(ddKCl) = 202,1 (g)
=> \(C\%KCl=\dfrac{0,2.74,5}{202,1}\cdot100\%\approx7,37\%\)
\(\begin{array}{l} a,\\ n_{K_2SO_4}=\dfrac{17,4}{174}=0,1\ (mol)\\ PTHH:K_2SO_4+BaCl_2\to BaSO_4\downarrow+2KCl\\ Theo\ pt:\ n_{BaSO_4}=n_{K_2SO_4}=0,1\ (mol)\\ \Rightarrow m_{BaSO_4}=0,1\times 233=23,3\ (g)\\ b,\\ Theo\ pt:\ n_{BaCl_2}=n_{K_2SO_4}=0,1\ (mol)\\ \Rightarrow m_{\text{dd BaCl_2}}=\dfrac{0,1\times 208}{10\%}=208\ (g)\\ m_{\text{dd spư}}=m_{K_2SO_4}+m_{\text{dd BaCl_2}}-m_{BaSO_4}\\ \Rightarrow m_{\text{dd spư}}=17,4+208-23,3=202,1\ (g)\\ Theo\ pt:\ n_{KCl}=2n_{K_2SO_4}=0,2\ (mol)\\ \Rightarrow C\%_{\text{dd spư}}=C\%_{KCl}=\dfrac{0,2\times 74,5}{202,1}\times 100\%=7,37\%\end{array}\)