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a. Ta có: \(n_{Fe_3O_4}=\dfrac{23,2}{232}=0,1\left(mol\right)\)
Ta lại có: \(C_{\%_{HCl}}=\dfrac{m_{ct_{HCl}}}{100}.100\%=7,3\%\)
=> mHCl = 7,3(g)
=> \(n_{HCl}=\dfrac{7,3}{36,5}=0,2\left(mol\right)\)
PTHH:
Fe3O4 + 8HCl ---> FeCl2 + 2FeCl3 + 4H2O
1 ---> 8
0,1 ---> 0,2
=> \(\dfrac{0,1}{1}>\dfrac{0,2}{8}\)
Vậy Fe3O4 dư
=> mdư = 23,2 - 7,3 = 15,9 (g)
b. Theo PT: \(n_{FeCl_2}=\dfrac{1}{8}.n_{HCl}=\dfrac{1}{8}.0,2=0,025\left(mol\right)\)
=> \(m_{FeCl_2}=0,025.127=3,175\left(g\right)\)
Theo PT: \(n_{FeCl_3}=\dfrac{1}{4}.n_{HCl}=\dfrac{1}{4}.0,2=0,05\left(mol\right)\)
=> \(m_{FeCl_3}=0,05.162,5=8,125\left(g\right)\)
=> \(m_{muối}=8,125+3,175=11,3\left(g\right)\)
c. Ta có: mdung dịch sau PỨ = \(23,2+100=123,2\left(g\right)\)
Theo PT: \(n_{H_2O}=\dfrac{1}{2}.n_{HCl}=\dfrac{1}{2}.0,2=0,1\left(mol\right)\)
=> \(m_{H_2O}=0,1.18=1,8\left(g\right)\)
mcác chất sau PỨ = 1,8 + 11,3 = 13,1(g)
=> \(C_{\%_{sauPỨ}}=\dfrac{13,1}{123,2}.100\%=10,63\%\)
a hả
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\(m_{ct}=\dfrac{2,84.100}{100}=2,84\left(g\right)\)
\(n_{Na2SO4}=\dfrac{2,84}{142}=0,02\left(mol\right)\)
a) Pt ; \(Na_2SO_4+Ba\left(NO_3\right)_2\rightarrow2NaNO_3+BaSO_4|\)
1 1 2 1
0,02 0,02 0,04 0,02
b) \(n_{Ba\left(NO3\right)2}=\dfrac{0,02.1}{1}=0,02\left(mol\right)\)
\(m_{Ba\left(NO3\right)2}=0,02.261=5,22\left(g\right)\)
\(m_{ddBa\left(NO3\right)2}=\dfrac{5,22.100}{2,088}=250\left(g\right)\)
c) \(n_{NaNO3}=\dfrac{0,02.2}{1}=0,04\left(mol\right)\)
⇒ \(m_{NaNO3}=0,04.85=3,4\left(g\right)\)
\(n_{BaSO4}=\dfrac{0,04.1}{2}=0,02\left(mol\right)\)
⇒ \(m_{BaSO4}=0,02.233=4,66\left(g\right)\)
\(m_{ddspu}=100+250-4,66=345,34\left(g\right)\)
\(C_{NaNO3}=\dfrac{3,4.100}{345,34}=0,98\)0/0
Chúc bạn học tốt
a, \(n_{Na_2SO_4}=100.2,84\%=2,84\left(g\right)\Rightarrow n_{Na_2SO_4}=\dfrac{2,84}{142}=0,02\left(mol\right)\)
PTHH: Na2SO4 + Ba(NO3)2 → 2NaNO3 + BaSO4
Mol: 0,02 0,02 0,04 0,02
b,\(m_{ddBa\left(NO_3\right)_2}=\dfrac{0,02.261.100}{2,088}=250\left(g\right)\)
c, mdd sau pứ = 100+250-0,02.233 = 345,34 (g)
\(C\%_{ddNaNO_3}=\dfrac{0,04.85.100\%}{345,34}=0,98\%\)
\(n_{FeO}=\dfrac{7,2}{72}=0,1mol\\ n_{H_2SO_4}=0,4.1,5=0,6mol\\ FeO+H_2SO_4\rightarrow FeSO_4+H_2O\\ \Rightarrow\dfrac{0,1}{1}< \dfrac{0,6}{1}\Rightarrow H_2SO_4.dư\\ n_{FeO}=n_{FeSO_4}=n_{H_2SO_4,pư}=0,1mol\\ C_{M_{FeSO_4}}=\dfrac{0,1}{0,4}=0,25M\\ C_{M_{H_2SO_4}}=\dfrac{0,6-0,1}{0,4}=1,25M\)
a)
$K_2SO_4 + BaCl_2 \to BaSO_4 + 2KCl$
b)
$n_{K_2SO_4} = 0,2.2 = 0,4(mol)$
$n_{BaCl_2} = 0,3.1 = 0,3(mol)$
Ta thấy :
$n_{K_2SO_4} : 1 > n_{BaCl_2} : 1$ nên $K_2SO_4$ dư
$n_{BaSO_4} = n_{BaCl_2} = 0,3(mol)$
$m_{BaSO_4} = 0,3.233 = 69,9(gam)$
c) $n_{K_2SO_4} = 0,4 - 0,3 = 0,1(mol)$
$V_{dd\ sau\ pư} = 0,2 + 0,3 = 0,5(lít)$
$C_{M_{K_2SO_4} } = \dfrac{0,1}{0,5} = 0,2M$
$C_{M_{KCl}} = \dfrac{0,6}{0,5} = 1,2M$
Ta có: \(n_{Ba}=\dfrac{8,22}{137}=0,06\left(mol\right)\)
Ta có: \(C_{\%_{H_2SO_4}}=\dfrac{m_{H_2SO_4}}{200}.100\%=1,96\%\)
=> \(m_{H_2SO_4}=3,92\left(g\right)\)
=> \(n_{H_2SO_4}=\dfrac{3,92}{98}=0,04\left(mol\right)\)
PTHH: Ba + H2SO4 ---> BaSO4↓ + H2
Ta thấy: \(\dfrac{0,06}{1}>\dfrac{0,04}{1}\)
=> Ba dư
Theo PT: \(n_{BaSO_4}=n_{H_2SO_4}=0,04\left(mol\right)\)
=> \(m_{BaSO_4}=0,04.233=9,32\left(g\right)\)
Theo PT: \(n_{H_2}=n_{H_2SO_4}=0,04\left(mol\right)\)
=> \(m_{H_2}=0,04.2=0,08\left(g\right)\)
Ta có: \(m_{dd_{BaSO_4}}=8,22+200-0,08=208,14\left(g\right)\)
=> \(C_{\%_{BaSO_4}}=\dfrac{9,32}{208,14}.100\%\approx4,48\%\)