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2Al+3H2SO4->Al2(SO4)3+3H2
0,2-----0,3-------0,1------------0,3
n Al=\(\dfrac{5,4}{27}\)=0,2 mol
n H2SO4= \(\dfrac{30}{98}\)=0,306 mol
=>H2SO4 còn dư
=>VH2=0,3.22,4=6,72l
=>m Al2(SO4)3=0,1.342=34,2g
=>m H2SO4 dư=0,006.98=0,588g
\(n_{Al}=\dfrac{m_{Al}}{M_{Al}}=\dfrac{5,4}{27}=0,2mol\)
\(n_{H_2SO_4}=\dfrac{m_{H_2SO_4}}{M_{H_2SO_4}}=\dfrac{30}{98}=\dfrac{15}{49}mol\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
2 3 1 3 ( mol )
0,2 15/49 ( mol )
Ta có: \(\dfrac{0,2}{2}< \dfrac{15}{49}:3\)
=> Chất còn dư là \(H_2SO_4\)
\(V_{H_2}=n_{H_2}.22,4=\left(\dfrac{0,2.3}{2}\right).22,4=6,72l\)
\(m_{Al_2\left(SO_4\right)_3}=n_{Al_2\left(SO_4\right)_3}.M_{Al_2\left(SO_4\right)_3}=\left(\dfrac{0,2.1}{2}\right).342=34,2g\)
\(m_{H_2SO_4\left(du\right)}=n_{H_2SO_4\left(du\right)}.M_{H_2SO_4}=\left(\dfrac{15}{49}-\dfrac{0,2.3}{2}\right).98=0,6g\)
2KClO3 \(\xrightarrow[MnO_2]{to}\) 2KCl + 3O2
\(n_{KClO_3}=\frac{7}{122,5}=\frac{2}{35}\left(mol\right)\)
\(n_{CO_2}=\frac{2,64}{44}=0,06\left(mol\right)\)
Ta có: \(V_{O_2}=V_{CO_2}\)
Theo ĐL Avogadro ⇒ \(n_{O_2}=n_{CO_2}=0,06\left(mol\right)\)
a) \(V_{O_2}=0,06\times22,4=1,344\left(l\right)\)
b) Theo pT: \(n_{KClO_3}pư=\frac{2}{3}n_{O_2}=\frac{2}{3}\times0,06=0,04\left(mol\right)\)
\(\Rightarrow n_{KClO_3}dư=\frac{2}{35}-0,04=\frac{3}{175}\left(mol\right)\)
\(\Rightarrow m_{KClO_3}dư=\frac{3}{175}\times122,5=2,1\left(g\right)\)
Theo pT: \(n_{KCl}=\frac{2}{3}n_{O_2}=\frac{2}{3}\times0,06=0,04\left(mol\right)\)
\(\Rightarrow m_{KCl}=0,04\times74,5=2,98\left(g\right)\)
\(m_{chấtrắn}saupư=2,1+2,98=5,08\left(g\right)\)
\(n_{FeO}=\dfrac{10,8}{72}=0,15\left(mol\right)\)
\(n_{H_2SO_4}=\dfrac{100.20\%}{100\%}:98=\dfrac{10}{49}\left(mol\right)\)
\(FeO+H_2SO_4\rightarrow FeSO_4+H_2O\)
0,15----> 0,15 -----> 0,15----->0,15
Xét \(\dfrac{10}{49}:1>\dfrac{0,15}{1}\) => axit dư.
Sau khi phản ứng kết thúc, trong dung dịch có:
\(m_{H_2SO_4}=\left(\dfrac{10}{49}-0,15\right).98=5,3\left(g\right)\)
\(m_{FeSO_4}=0,15.152=22,8\left(g\right)\)
\(m_{H_2O}=0,15.18=2,7\left(g\right)\)
Fe2O3 + 3H2 \(\underrightarrow{to}\) 2Fe + 3H2O
\(n_{Fe}=\frac{11,2}{56}=0,2\left(mol\right)\)
a) Theo pT: \(n_{Fe_2O_3}pư=\frac{1}{3}n_{H_2}=\frac{1}{2}\times0,2=0,1\left(mol\right)\)
\(\Rightarrow m_{Fe_2O_3}=0,1\times160=16\left(g\right)\)
b) Theo PT: \(n_{H_2}pư=\frac{3}{2}n_{Fe}=\frac{3}{2}\times0,2=0,3\left(mol\right)\)
\(\Rightarrow V_{H_2}pư=0,3\times22,4=6,72\left(l\right)\)
c) \(m_{Fe_2O_3}dư=40-16=24\left(g\right)\)
\(m_X=m_{Fe_2O_3}dư+m_{Fe}=24+11,2=35,2\left(g\right)\)
nFe = 11,2 / 56 = 0,2 (mol)
Fe2O3 + 3H2 → 2Fe + 3H2O (t\(^o\))
mol pư: 0,1.←0,3 ←0,2
a, Vậy : m(Fe2O3 bị khử) = 0,1 * 160 = 16 (gam)
b, Vậy : V(H2 pư) = 0,3 * 22,4 = 6,72 (lít)
c, m(X) = m(Fe) + mFe2O3(dư)
= 11,2 + 40 - 16
= 35,2 (gam)
\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\\
n_{H_2SO_4}=\dfrac{24,5}{98}=0,25\left(mol\right)\\
pthh:Fe+H_2SO_4\rightarrow FeSO_4+H_2\uparrow\)
\(LTL:\dfrac{0,2}{1}< \dfrac{0,25}{1}\)
=> H2SO4 dư
\(n_{H_2}=n_{H_2SO_4\left(p\text{ư}\right)}=n_{Fe}=0,2\left(mol\right)\\
V_{H_2}=0,2.22,4=4,48l\\
m_{H_2SO_4\left(d\right)}=\left(0,25-0,2\right).98=4,9g\)
Bài 1:
nH2SO4 bđ = 0,5 . 0,2 = 0,1 mol
nH2 = \(\dfrac{1,792}{22,4}=0,08\left(mol\right)\)
Pt: Zn + H2SO4 --> ZnSO4 + H2
............0,08 mol<-0,08 mol<-0,08 mol
Theo pt: nH2SO4 pứ = nH2 = 0,08 mol < 0,1 mol
=> HCl dư
CM H2SO4 dư = \(\dfrac{\left(0,1-0,08\right)}{0,2}=0,1M\)
CM ZnSO4 = \(\dfrac{0,08}{0,2}=0,4M\)
Bài 2:
nCuO = \(\dfrac{3,2}{80}=0,04\left(mol\right)\)
mH2SO4 = \(\dfrac{150\times32,666}{100}=49\left(g\right)\)
nH2SO4 = \(\dfrac{49}{98}=0,5\left(mol\right)\)
Pt: CuO + H2SO4 --> CuSO4 + H2O
0,04 mol->0,04 mol->0,04 mol
Xét tỉ lệ mol giữa CuO và H2SO4:
\(\dfrac{0,04}{1}< \dfrac{0,5}{1}\)
Vậy H2SO4 dư
mH2SO4 dư = (0,5 - 0,04) . 98 = 45,08 (g)
mCuSO4 = 0,04 . 160 = 6,4 (g)
mdd sau pứ = mCuO + mdd H2SO4 = 3,2 + 150 = 153,2 (g)
C% dd CuSO4 = \(\dfrac{6,4}{153,2}.100\%=4,177\%\)
C% dd H2SO4 dư = \(\dfrac{45,08}{153,2}.100\%=29,425\%\)
a, Fe2O3 + 3H2SO4 ---> Fe2(SO4)3 + 3H2O
Ta có nFe2O3= 24/160=0,15
nH2SO4 = 300.19,4/(100.98)=0,6
Ta có 0,15 < 0,6/3=0,2
=> H2SO4 dư , Fe2O3 hết
=> nFe2(SO4)3 =nFe2O3=0,15
=> m muối=0,15.400=60 g
b, Ta có m dd sau PỨ = 24 + 300=324 g
=> C% dd sau PỨ = 60.100/324=18,51%