\(n_{Fe_2O_3}=\dfrac{8}{160}=0,05\left(mol\right)\)

PTHH: Fe₂O₃ + 3H₂SO₄ --> Fe₂(SO₄)₃ + 3H₂O

______0,05------>0,15--------->0,05

=> m_H2SO4 = 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%`

100.\(\approx\)

\(m_{CH_3COOH}=24\%.150=36\left(g\right)\\ \rightarrow n_{CH_3COOH}=\dfrac{36}{60}=0,6\left(mol\right)\)

PTHH: 2CH₃COOH + Na₂CO₃ ---> 2CH₃COONa + CO₂ + H₂O

                0,6                  0,3                  0,6                  0,3 

=> V_CO2 = 0,3.22,4 = 6,72 (l)

\(m_{Na_2CO_3}=0,3.31,8\left(g\right)\)

=> \(m_{ddNa_2CO_3}=\dfrac{31,8}{21,2\%}=150\left(g\right)\)

m_CO2 = 0,3.44 = 13,2 (g)

\(m_{dd}=150+150-13,2=286,8\left(g\right)\)

\(m_{CH_3COONa}=0,3.82=24,6\left(g\right)\\ \rightarrow C\%_{CH_3COONa}=\dfrac{24,6}{286,8}=8,58\%\)

\(n_{FeO}=\dfrac{10.8}{72}=0.15\left(mol\right)\)

\(FeO+2HCl\rightarrow FeCl_2+H_2O\)

\(0.15.......0.3.............0.15\)

\(m_{HCl}=0.3\cdot36.5=10.95\left(g\right)\)

\(C\%HCl=\dfrac{10.95}{100}\cdot100\%=10.95\%\)

\(m_{dd}=10.8+100=110.8\left(g\right)\)

\(m_{FeCl_2}=0.15\cdot127=19.05\left(g\right)\)

\(C\%FeCl_2=\dfrac{19.05}{110.8}\cdot100\%=17.19\%\)

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)

\(n_{CH_3COOH}=\dfrac{100.12\%}{60}=0,2\left(mol\right)\)

PTHH: CH₃COOH + NaHCO₃ --> CH₃COONa + CO₂ + H₂O

                    0,2------>0,2-------------->0,2------->0,2

=> \(m_{dd.NaHCO_3.8,4\%}=\dfrac{0,2.84.100}{8,4}=200\left(g\right)\)

m_{dd 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, $m_{dd} = 11,2 + 200 - 0,2.2 = 210,8(gam)$
$C\%_{FeCl_2} = \dfrac{0,2.127}{210,8}.100\% = 12,05\%$

nNaOH = 4/40 = 0.1 (mol)

PTHH: NaOH + HCl -> NaCl + H2O

Từ PTHH: nNaCl = nHCl = nNaOH = 0.1 (mol)

a) mNaCl = 0.1*(23+35.5) = 5.85(g)

b) mHCl = 0.1*(1+35.5) = 3.65(g)

C%ddHCl = 3.65/100 * 100% = 3.65%