Cho 100 gam dung dịch CH3COOH 12% tác dụng vừa đủ với m gam CaCO3. (a) Hãy tính khối lượng CaCO3 đã phản ứng. (b) Hãy tính nồng độ phần trăm của dung dịch muối thu được sau phản ứng.
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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)
PTHH: \(CH_3COOH+KHCO_3\rightarrow CH_3COOK+H_2O+CO_2\uparrow\)
a) Ta có: \(n_{CH_3COOH}=\dfrac{200\cdot24\%}{60}=0,8\left(mol\right)=n_{KHCO_3}\)
\(\Rightarrow m_{ddKHCO_3}=\dfrac{0,8\cdot100}{16,8\%}\approx476.2\left(g\right)\)
b) Theo PTHH: \(n_{CH_3COOK}=0,8\left(mol\right)=n_{CO_2}\)
\(\Rightarrow\left\{{}\begin{matrix}m_{CH_3COOK}=0,8\cdot98=78,4\left(g\right)\\m_{CO_2}=0,8\cdot44=35,2\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd}=m_{ddCH_3COOH}+m_{ddKHCO_3}-m_{CO_2}=641\left(g\right)\)
\(\Rightarrow C\%_{CH_3COOK}=\dfrac{78,4}{641}\cdot100\%\approx12,23\%\)
`a)PTHH:`
`Mg + H_2 SO_4 -> MgSO_4 + H_2`
`0,2` `0,2` `0,2` `(mol)`
`n_[Mg]=[4,8]/24=0,2(mol)`
`b)m_[MgSO_4]=0,2.120=24(g)`
`c)C%_[MgSO_4]=24/[4,8+50-0,2.2].100~~44,12%`
\(m_{CH_3COOH}=24\%.150=36\left(g\right)\\ \rightarrow n_{CH_3COOH}=\dfrac{36}{60}=0,6\left(mol\right)\)
PTHH: 2CH3COOH + Na2CO3 ---> 2CH3COONa + CO2 + H2O
0,6 0,3 0,6 0,3
=> VCO2 = 0,3.22,4 = 6,72 (l)
\(m_{Na_2CO_3}=0,3.31,8\left(g\right)\)
=> \(m_{ddNa_2CO_3}=\dfrac{31,8}{21,2\%}=150\left(g\right)\)
mCO2 = 0,3.44 = 13,2 (g)
\(m_{dd}=150+150-13,2=286,8\left(g\right)\)
\(m_{CH_3COONa}=0,3.82=24,6\left(g\right)\\ \rightarrow C\%_{CH_3COONa}=\dfrac{24,6}{286,8}=8,58\%\)
\(n_{FeO}=\dfrac{10.8}{72}=0.15\left(mol\right)\)
\(FeO+2HCl\rightarrow FeCl_2+H_2O\)
\(0.15.......0.3.............0.15\)
\(m_{HCl}=0.3\cdot36.5=10.95\left(g\right)\)
\(C\%HCl=\dfrac{10.95}{100}\cdot100\%=10.95\%\)
\(m_{dd}=10.8+100=110.8\left(g\right)\)
\(m_{FeCl_2}=0.15\cdot127=19.05\left(g\right)\)
\(C\%FeCl_2=\dfrac{19.05}{110.8}\cdot100\%=17.19\%\)
nFeO=10.872=0.15(mol)nFeO=10.872=0.15(mol)
FeO+2HCl→FeCl2+H2OFeO+2HCl→FeCl2+H2O
0.15.......0.3.............0.150.15.......0.3.............0.15
mHCl=0.3⋅36.5=10.95(g)mHCl=0.3⋅36.5=10.95(g)
C%HCl=10.95100⋅100%=10.95%C%HCl=10.95100⋅100%=10.95%
mdd=10.8+100=110.8(g)mdd=10.8+100=110.8(g)
mFeCl2=0.15⋅127=19.05(g)mFeCl2=0.15⋅127=19.05(g)
C%FeCl2=19.05110.8⋅100%=17.19%C%FeCl2=19.05110.8⋅100%=17.19%
\(n_{CH_3COOH}=\dfrac{100.12\%}{60}=0,2\left(mol\right)\)
PTHH: CH3COOH + NaHCO3 --> CH3COONa + CO2 + H2O
0,2------>0,2-------------->0,2------->0,2
=> \(m_{dd.NaHCO_3.8,4\%}=\dfrac{0,2.84.100}{8,4}=200\left(g\right)\)
mdd sau pư = 100 + 200 - 0,2.44 = 291,2 (g)
\(m_{CH_3COONa}=0,2.82=16,4\left(g\right)\)
=> \(C\%_{CH_3COONa}=\dfrac{16,4}{291,2}.100\%=5,632\%\)
a) $n_{Fe} = \dfrac{11,2}{56} = 0,2(mol)$
$Fe + 2HCl \to FeCl_2 + H_2$
$n_{HCl} =2 n_{Fe} = 0,2.2 = 0,4(mol)$
$C\%_{HCl} = \dfrac{0,4.36,5}{200}.100\% = 7,3\%$
b) $n_{H_2} = n_{FeCl_2} = n_{Fe} = 0,2(mol)
Sau phản ứng, $m_{dd} = 11,2 + 200 - 0,2.2 = 210,8(gam)$
$C\%_{FeCl_2} = \dfrac{0,2.127}{210,8}.100\% = 12,05\%$