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\(a,PTHH:Na_2O+H_2O\rightarrow2NaOH\\ \Rightarrow n_{NaOH}=2n_{Na_2O}=2\cdot\dfrac{37,2}{62}=0,6\cdot2=1,2\left(mol\right)\\ \Rightarrow C_{M_{NaOH}}=\dfrac{1,2}{0,5}=2,4M\\ b,PTHH:2NaOH+H_2SO_4\rightarrow Na_2SO_4+H_2O\\ \Rightarrow n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,6\left(mol\right)\\ \Rightarrow m_{H_2SO_4}=0,6\cdot98=58,8\left(g\right)\\ \Rightarrow m_{dd_{H_2SO_4}}=\dfrac{58,8\cdot100\%}{20\%}=294\left(g\right)\\ \Rightarrow V_{dd}=\dfrac{294}{1,14}\approx257,9\left(ml\right)\)
PTHH: \(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)
Ta có: \(n_{CO_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{Na_2CO_3}=0,3\left(mol\right)\\n_{NaOH}=0,6\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}C\%_{NaOH}=\dfrac{0,6\cdot40}{240}\cdot100\%=10\%\\C\%_{Na_2CO_3}=\dfrac{0,3\cdot106}{240+0,3\cdot44}\cdot100\%\approx12,56\%\end{matrix}\right.\)
1. \(n_{Na_2O}=\dfrac{15,5}{62}=0,25\left(mol\right)\)
PTHH: Na2O + H2O → 2NaOH
Mol: 0,25 0,5
\(C_{M_{ddNaOH}}=\dfrac{0,5}{0,5}=1M\)
2.
PTHH: 2NaOH + H2SO4 → Na2SO4 + 2H2O
Mol: 0,5 0,25
\(m_{ddH_2SO_4}=\dfrac{0,25.98.100}{20}=122,5\left(g\right)\)
\(V_{ddH_2SO_4}=\dfrac{122,5}{1,14}=107,456\left(ml\right)\)
\(n_{Na2O}=\dfrac{m_{Na2O}}{M_{Na2O}}=0,25\left(mol\right)\)
\(Na_2O+H_2O\rightarrow2NaOH\)
0,25 mol - 0,25 mol - 0,5 mol
a) \(C_{M_{NaOH}}=\dfrac{n_{NaOH}}{V_{NaOH}}=1\left(M\right)\)
b) \(H_2SO_4+2NaOH\rightarrow Na_2SO4+2H_2O\)
0,25 mol - 0,5 mol - 0,25 mol - 0,5 mol
\(m_{ctH2SO4}=n_{H2SO4}.M_{H2SO4}=24,5\left(g\right)\)
\(C_{\%_{H2SO4}}=\dfrac{m_{ctH2SO4}}{m_{ddH2SO4}}.100\%\)
\(\Rightarrow m_{ddH2SO4}=\dfrac{m_{ctH2SO4}.100\%}{C_{\%_{H2SO4}}}=122,5\left(g\right)\)
\(D_{H2SO4}=\dfrac{m_{ddH2SO4}}{V_{H2SO4}}\Rightarrow V_{H2SO4}=\dfrac{m_{ddH2SO4}}{D_{H2SO4}}\approx107,46\left(ml\right)\)
a, \(CuCl_2+2NaOH\rightarrow2NaCl+Cu\left(OH\right)_2\)
b, \(n_{NaOH}=\dfrac{10}{40}=0,25\left(mol\right)\)
Theo PT: \(n_{CuCl_2}=n_{Cu\left(OH\right)_2}=\dfrac{1}{2}n_{NaOH}=0,125\left(mol\right)\)
\(\Rightarrow m_{Cu\left(OH\right)_2}=0,125.98=12,25\left(g\right)\)
c, \(C_{M_{CuCl_2}}=\dfrac{0,125}{0,1}=1,25\left(M\right)\)
\(n_{NaOH}=\dfrac{10}{40}=0,25\left(mol\right)\)
PTHH:
\(CuCl_2+2NaOH\rightarrow Cu\left(OH\right)_2+2NaCl\)
0,125 0,25 0,125 0,25
\(m_{Cu\left(OH\right)_2}=0,125.98=12,25\left(g\right)\)
\(C_{M\left(CuCl_2\right)}=\dfrac{0,125}{0,1}=1,25\left(M\right)\)
\(CH_3COOH+NaOH\rightarrow CH_3COONa+H_2O\\ n_{NaOH}=0,2.0,1=0,02\left(mol\right)\\ n_{CH_3COOH}=n_{NaOH}=0,02\left(mol\right)\\ C_{MddCH_3COOH}=\dfrac{0,02}{0,1}=0,2\left(M\right)\)
a) PTHH: Na2O + H20 -> 2NaOH
số mol Na20 = 0,25 (mol)
=> số mol NaOH = 0,5 mol.
Nôngd độ mol NaOH = 0,5 / 0,5 = 1 M
b) PTHH: H2SO4 + 2NaOH -> Na2SO4 + 2H2O
số mol H2SO4 = 1/2 số mol NaOH = 0,25 mol
C% H2SO4 = mH2SO4 / m ddH2SO4 . 100%
=> m ddH2SO4= 122,5 g
D=m/V => V= 107,5 ml
Số mol Na2O = 15,5:62 = 0,25 mol
a) Khi cho Na2O xảy ra phản ứng, tạo thành phản ứng dung dịch có chất tan là NaOH.
Na2O + H2O → 2NaOH
Phản ứng: 0,25 → 0,05 (mol)
500 ml = = 0,5 lít; CM, NaOH =
= 1M.
b) Phương trình phản ứng trung hòa dung dịch:
2NaOH + H2SO4 → Na2SO4 + 2H2O
Phản ứng: 0, 5 → 0,25 0,25 (mol)
mH2SO4 = 0,25x98 = 24,5 g
mdd H2SO4 = = 122,5 g
mdd, ml = =
≈ 107,5 ml
a, \(Na_2O+H_2O\rightarrow2NaOH\)
Ta có: \(n_{Na_2O}=\dfrac{15,5}{62}=0,25\left(mol\right)\)
Theo PT: \(n_{NaOH}=2n_{Na_2O}=0,5\left(mol\right)\)
\(\Rightarrow CM_{NaOH}=\dfrac{0,5}{0,5}=1\left(M\right)\)
b, \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
Theo PT: \(n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=0,25\left(mol\right)\)
\(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,25.98}{20\%}=122,5\left(g\right)\)
\(\Rightarrow V_{ddH_2SO_4}=\dfrac{122,5}{1,14}\approx107,46\left(ml\right)\)
cau 1