Người ta dùng dung dịch H 2 SO 4 để trung hoà vừa đủ 200g dung dịch NaOH 10%.Tính khối lượng axit sunphuric đã dùng.
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Theo đề bài ta có :
nFe = 1,68/56 = 0,03 mol
a) Ta có PTHH :
2NaOH + H2SO4 -> Na2SO4 + 2H2O
0,1mol......0,05mol
=> CMH2SO4 = 0,05/0,05=1
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 9 :
\(a) n_{Fe_2O_3} = \dfrac{3,2}{160}=0,02(mol)\\ Fe_2O_3 + 3H_2SO_4 \to Fe_2(SO_4)_3 + 3H_2O\\ n_{H_2SO_4} = 3n_{Fe_2O_3} = 0,06(mol)\\ m_{dd\ H_2SO_4} = \dfrac{0,06.98}{19,6\%} = 30(gam)\\ b) \text{Chất tan : } Fe_2(SO_4)_3\\ n_{Fe_2(SO_4)_3} = n_{Fe_2O_3} = 0,02(mol)\\ m_{Fe_2(SO_4)_3} = 0,02.400 =8(gam)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(n_{H_2SO_4}=\dfrac{200.9,8}{100.98}=0,2\left(mol\right)\)
PTHH: 2NaOH + H2SO4 --> Na2SO4 + 2H2O
______0,4<------0,2
=> \(V_{dd}=\dfrac{0,4}{1}=0,4\left(l\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(n_{Fe_2O_3}=\dfrac{3,2}{160}=0,02(mol)\\ PTHH:Fe_2O_3+3H_2SO_4\to Fe_2(SO_4)_3+3H_2\\ \Rightarrow n_{H_2SO_4}=3n_{Fe_2O_3}=0,06(mol)\\ \Rightarrow m_{dd_{H_2SO_4}}=\dfrac{0,06.98}{19,6\%}=30(g)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(CaO+2HCl\rightarrow CaCl_2+H_2O\)
\(HCl+NaOH\rightarrow NaCl+H_2O\)
b) \(n_{CaO}=\dfrac{2,8}{56}=0,05\left(mol\right);n_{NaOH}=\dfrac{100.4\%}{40}=0,1\left(mol\right)\)
\(m_{muối}=m_{CaCl_2}+m_{NaCl}=0,05.111+0,1.58,5=11,4\left(g\right)\)
c) \(CM_{HCl}=\dfrac{0,05.2+0,1}{0,5}=0,4M\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a, Ta có: \(m_{NaOH}=200.4\%=8\left(g\right)\) \(\Rightarrow n_{NaOH}=\dfrac{8}{40}=0,2\left(mol\right)\)
PT: \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
_____0,2______0,1_______0,1 (mol)
\(\Rightarrow V_{ddH_2SO_4}=\dfrac{0,1}{0,2}=0,5M\)
b, Ta có: m dd sau pư = m dd NaOH + m ddH2SO4 = 200 + 50 = 250 (g)
\(\Rightarrow C\%_{Na_2SO_4}=\dfrac{0,1.142}{250}.100\%=5,68\%\)
Bạn tham khảo nhé!
![](https://rs.olm.vn/images/avt/0.png?1311)
a)
$CuO + H_2SO_4 \to CuSO_4 + H_2O$
$n_{H_2SO_4} = n_{CuO} = \dfrac{1,6}{80} = 0,02(mol)$
$C\%_{H_2SO_4} = \dfrac{0,02.98}{100}.100\% = 1,96\%$
b)
$2NaOH + H_2SO_4 \to Na_2SO_4 + 2H_2O$
$n_{NaOH} = 2n_{H_2SO_4} = 0,04(mol)$
$m_{NaOH} = 0,04.40 = 1,6(gam)$
c)
$Cu + 2H_2SO_4 \to CuSO_4 + SO_2 + 2H_2O$
Cu dư nên $n_{SO_2} = \dfrac{1}{2}n_{H_2SO_4} = 0,05(mol)$
$V_{SO_2} = 0,05.22,4 = 1,12(lít)$
![](https://rs.olm.vn/images/avt/0.png?1311)
\(n_{Fe_2O_3}=\dfrac{48}{160}=0,3(mol)\\ PTHH:Fe_2O_3+3H_2SO_4\to Fe_2(SO_4)_3+3H_2O\\ \Rightarrow n_{H_2SO_4}=3n_{Fe_2O_3}=0,9(mol)\\ \Rightarrow m_{dd_{H_2SO_4}}=\dfrac{0,9.98}{19,6\%}=450(g)\)
\(m_{NaOH}=\dfrac{200\cdot10\%}{100\%}=20\left(g\right)\\ \Rightarrow n_{NaOH}=\dfrac{20}{40}=0,5\left(mol\right)\\ PTHH:2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\\ \Rightarrow n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,25\left(mol\right)\\ \Rightarrow m_{H_2SO_4}=0,25\cdot98=24,5\left(g\right)\)