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19 tháng 9 2021

a) \(n_{Na}=\dfrac{2,3}{23}=0,1\left(mol\right)\)

PTHH: 2Na + 2H2O → 2NaOH + H2

Mol:     0,1                         0,1        0,05

\(m_{NaOH}=0,1.40=4\left(g\right)\)

b) \(m_{H_2O}=47,8.1=47,8\left(g\right)\)

 \(m_{ddNaOH}=2,3+47,8-0,05.2=50\left(g\right)\)

c) \(C\%_{ddNaOH}=\dfrac{4.100\%}{50}=8\%\)

4 tháng 10 2021

200ml = 0,2l

\(n_{Zn}=\dfrac{19,5}{65}=0,3\left(mol\right)\)

Pt : \(Zn+2HCl\rightarrow ZnCl_2+H_2|\)

        1         2              1           1

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

a) \(n_{ZnCl2}=\dfrac{0,3.1}{1}=0,3\left(mol\right)\)

\(C_{M_{ZnCl2}}=\dfrac{0,3}{0,2}=1,5\left(M\right)\)

b) \(n_{H2}=\dfrac{0,3.1}{1}=0,3\left(mol\right)\)

\(V_{H2\left(dktc\right)}=0,3.22,4=6,72\left(l\right)\)

c) Pt : \(NaOH+HCl\rightarrow NaCl+H_2O|\)

              1            1              1            1

            0,6          0,6

\(n_{NaOH}=\dfrac{0,6.1}{1}=0,6\left(mol\right)\)

\(m_{NaOH}=0,6.40=24\left(g\right)\)
\(m_{ddNaOH}=\dfrac{24.100}{20}=120\left(g\right)\)

 Chúc bạn học tốt

19 tháng 12 2023

a, \(HCl+NaOH\rightarrow NaCl+H_2O\)

b, \(n_{HCl}=0,3.2=0,6\left(mol\right)\)

Theo PT: \(n_{NaOH}=n_{NaCl}=n_{HCl}=0,6\left(mol\right)\)

\(\Rightarrow m_{NaOH}=0,6.40=24\left(g\right)\)

\(\Rightarrow m_{ddNaOH}=\dfrac{24}{20\%}=120\left(g\right)\)

c, \(m_{NaCl}=0,6.58,5=35,1\left(g\right)\)

11 tháng 12 2020

PTHH: \(2NaOH+CuSO_4\rightarrow Na_2SO_4+Cu\left(OH\right)_2\downarrow\)

a) Ta có: \(n_{CuSO_4}=\dfrac{320\cdot20\%}{160}=0,4\left(mol\right)=n_{Cu\left(OH\right)_2}\) \(\Rightarrow m_{Cu\left(OH\right)_2}=0,4\cdot98=39,2\left(g\right)\)

b) Theo PTHH: \(n_{NaOH}=2n_{CuSO_4}=0,8mol\) \(\Rightarrow m_{ddNaOH}=\dfrac{0,8\cdot40}{10\%}=320\left(g\right)\)

c) Theo PTHH: \(n_{Na_2SO_4}=n_{CuSO_4}=0,4mol\) \(\Rightarrow m_{Na_2SO_4}=0,4\cdot142=56,8\left(g\right)\)

Mặt khác: \(m_{dd}=m_{ddNaOH}+m_{ddCuSO_4}-m_{Cu\left(OH\right)_2}=600,8\left(g\right)\)

\(\Rightarrow C\%_{Na_2SO_4}=\dfrac{56,8}{600,8}\cdot100\%\approx9,45\%\) 

29 tháng 6 2021

\(n_{FeCl_2}=\dfrac{150\cdot12.7\%}{127}=0.15\left(mol\right)\)

\(n_{NaOH}=\dfrac{350\cdot4\%}{40}=0.35\left(mol\right)\)

\(FeCl_2+2NaOH\rightarrow Fe\left(OH\right)_2+2NaCl\)

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

\(m_{Fe\left(OH\right)_3}=0.15\cdot90=13.5\left(g\right)\)

\(m_{dd}=150+350-13.5=486.5\left(g\right)\)

\(C\%_{NaCl}=\dfrac{0.3\cdot58.5}{486.5}\cdot100\%=3.61\%\)

\(C\%_{NaOH\left(dư\right)}=\dfrac{\left(0.35-0.3\right)\cdot40}{486.5}\cdot100\%=0.4\%\)

\(Fe\left(OH\right)_2\underrightarrow{^{^{t^0}}}FeO+H_2O\)

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

\(m_{FeO}=0.15\cdot72=10.8\left(g\right)\)

\(4Fe\left(OH\right)_2+O_2\underrightarrow{^{^{t^0}}}2Fe_2O_3+4H_2O\)

\(0.15.........................0.075\)

\(m_{Fe_2O_3}=0.075\cdot160=12\left(g\right)\)

19 tháng 9 2021

a, \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

PTHH: Fe + 2HCl → FeCl2 + H2

Mol:     015    0,3         0,15     0,15

b, \(m_{Fe}=0,15.56=8,4\left(g\right)\)

    \(m_{FeCl_2}=0,15.127=19,05\left(g\right)\)

c, \(C_{M_{ddHCl}}=\dfrac{0,3}{0,05}=6M\)

19 tháng 9 2021

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14 tháng 4 2022

a) \(n_{CH_3COOH}=0,1.0,3=0,03\left(mol\right)\)

PTHH: CH3COOH + NaOH --> CH3COONa + H2O

                  0,03---->0,03--------->0,03

=> \(V_{dd.NaOH}=\dfrac{0,03}{1,5}=0,02\left(l\right)\)

b) mCH3COONa = 0,03.82 = 2,46 (g)

c) \(C_{M\left(CH_3COONa\right)}=\dfrac{0,03}{0,1+0,02}=0,25M\)

16 tháng 11 2021

\(a,PTHH:FeCl_3+3NaOH\rightarrow Fe\left(OH\right)_3\downarrow+3NaCl\\ \Rightarrow n_{Fe\left(OH\right)_2}=n_{FeCl_3}=\dfrac{10,7}{107}=0,1\left(mol\right)\\ \Rightarrow m_{CT_{FeCl_3}}=0,1\cdot162,5=16,25\left(g\right)\\ \Rightarrow m_{dd_{FeCl_3}}=\dfrac{16,25\cdot100\%}{5\%}=325\left(g\right)\\ b,n_{NaOH}=n_{NaCl}=3n_{Fe\left(OH\right)_3}=0,3\left(mol\right)\\ \Rightarrow m_{NaOH}=0,3\cdot40=12\left(g\right)\\ m_{NaCl}=0,3\cdot58,5=17,55\left(g\right)\\ \Rightarrow m_{dd_{NaCl}}=325+150-10,7=464,3\left(g\right)\\ \Rightarrow C\%_{dd_{NaCl}}=\dfrac{17,55}{464,3}\cdot100\%\approx3,78\%\)

7 tháng 9 2023

\(a)2Na+2H_2O\rightarrow2NaOH+H_2\\ b)n_{Na}=\dfrac{6,9}{23}=0,3mol\\2Na+2H_2O\rightarrow2NaOH+H_2\)

0,3            0,3          0,3            0,15

\(V_{H_2}=0,15.24,79=3,7455l\\ c)m_{NaOH}=0,3.40=12g\\ d)C_{\%NaOH}=\dfrac{12}{6,9+100-0,15.2}\cdot100=11,19\%\)