cho 2.3g Natri tam hết trong 47.8ml nước thu được dung dịch NAOH và khí Hidro sinh ra
a) Tính khối lượng NAOH sinh ra
b) Tính khối lượng dung dịch NAOH thu được
c) Tính nồng độ % của dung dịch sau phản ứng
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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
PTHH: \(2NaOH+H_2SO_4\rightarrow Na_2SO_4+2H_2O\)
Ta có: \(n_{Na_2SO_4}=n_{H_2SO_4}=\dfrac{1}{2}n_{NaOH}=\dfrac{1}{2}\cdot\dfrac{10}{40}=0,125\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}m_{ddH_2SO_4}=\dfrac{0,125\cdot98}{10\%}=122,5\left(g\right)\\m_{Na_2SO_4}=0,125\cdot142=17,75\left(g\right)\end{matrix}\right.\)
\(\Rightarrow C\%_{Na_2SO_4}=\dfrac{17,75}{10+122,5}\cdot100\%\approx13,4\%\)
\(n_{CuSO_4}=\dfrac{200.16\%}{160}=0,2\left(mol\right)\)
PTHH :
\(CuSO_4+2NaOH\rightarrow Cu\left(OH\right)_2\downarrow+Na_2SO_4\)
0,2 0,4 0,2 0,2
\(m_{NaOH}=0,4.40=16\left(g\right)\)
\(m_{ddNaOH}=\dfrac{16.100}{10}=160\left(g\right)\)
\(c,m_{Na_2SO_4}=0,2.142=28,4\left(g\right)\)
\(m_{ddNa_2SO_4}=200+160-\left(0,2.98\right)=340,4\left(g\right)\)
\(C\%_{Na_2SO_4}=\dfrac{28,4}{240,4}.100\%\approx8,34\%\)
\(d,PTHH:\)
\(Cu\left(OH\right)_2\underrightarrow{t^o}CuO+H_2O\)
0,2 0,2
\(m_{CuO}=0,2.80=16\left(g\right)\)
a, \(CuSO_4+2NaOH\rightarrow Cu\left(OH\right)_2+Na_2SO_4\)
b, \(m_{CuSO_4}=200.16\%=32\left(g\right)\Rightarrow n_{CuSO_4}=\dfrac{32}{160}=0,2\left(mol\right)\)
\(n_{NaOH}=2n_{CuSO_4}=0,4\left(mol\right)\Rightarrow m_{ddNaOH}=\dfrac{0,4.40}{10\%}=160\left(g\right)\)
c, \(n_{Cu\left(OH\right)_2}=n_{Na_2SO_4}=n_{CuSO_4}=0,2\left(mol\right)\)
\(\Rightarrow C\%_{Na_2SO_4}=\dfrac{0,2.142}{200+160-0,2.98}.100\%\approx8,34\%\)
d, \(Cu\left(OH\right)_2\underrightarrow{t^o}CuO+H_2O\)
\(n_{CuO}=n_{Cu\left(OH\right)_2}=0,2\left(mol\right)\Rightarrow m_{CuO}=0,2.80=16\left(g\right)\)
PTHH: \(SO_2+2NaOH\rightarrow Na_2SO_3+H_2O\)
Ta có: \(n_{NaOH}=0,4\cdot2=0,8\left(mol\right)\)
\(\Rightarrow n_{SO_2}=0,4\left(mol\right)=n_{Na_2SO_3}\) \(\Rightarrow\left\{{}\begin{matrix}V_{SO_2}=0,4\cdot22,4=8,96\left(l\right)\\m_{Na_2SO_3}=0,4\cdot126=50,4\left(g\right)\\C_{M_{Na_2SO_3}}=\dfrac{0,4}{0,4}=1\left(M\right)\end{matrix}\right.\)
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: \(m_{dd}=m_{ddNaOH}+m_{ddCuSO_4}-m_{Cu\left(OH\right)_2}=600,8\left(g\right)\)
\(\Rightarrow C\%_{Na_2SO_4}=\dfrac{56,8}{600,8}\cdot100\%\approx9,45\%\)
400ml = 0,4l
\(n_{NaOH}=2.0,4=0,8\left(mol\right)\)
a) Pt : \(SO_2+2NaOH\rightarrow Na_2SO_3+H_2O|\)
1 2 1 1
0,4 0,8 0,4
b) \(n_{SO2}=\dfrac{0,8.1}{2}=0,4\left(mol\right)\)
\(V_{SO2\left(dktc\right)}=0,4.22,4=8,96\left(l\right)\)
c) \(n_{Na2SO3}=\dfrac{0,8.1}{2}=0,4\left(mol\right)\)
⇒ \(m_{Na2SO3}=0,4.126=50,4\left(g\right)\)
c) \(C_{M_{Na2SO3}}=\dfrac{0,4}{0,4}=1\left(M\right)\)
Chúc bạn học tốt
\(n_{H_2SO_4}=\dfrac{200.7,35\%}{98}=0,15\left(mol\right)\)
PTHH: 2NaOH + H2SO4 --> Na2SO4 + 2H2O
0,3<----0,15-------->0,15
=> mNaOH = 0,3.40 = 12 (g)
\(m_{dd.NaOH}=\dfrac{12.100}{8}=150\left(g\right)\)
mdd sau pư = 200 + 150 = 350 (g)
mNa2SO4 = 0,15.142 = 21,3 (g)
=> \(C\%_{dd.Na_2SO_4}=\dfrac{21,3}{350}.100\%=6,086\%\)
\(n_{Na}=\dfrac{6,9}{23}=0,3\left(mol\right)\\ 2Na+2H_2O\rightarrow2NaOH+H_2\\ n_{H_2}=\dfrac{0,3}{2}=0,15\left(mol\right)\\ a,V_{H_2\left(đktc\right)}=0,15.22,4=3,36\left(l\right)\\ b,m_{ddsaup.ứ}=m_{Na}+m_{H_2O}-m_{H_2}=6,9+100-0,15.2=106,6\left(g\right)\)
\(n_{FeCl_2}=\dfrac{150\cdot12.7\%}{127}=0.15\left(mol\right)\)
\(n_{NaOH}=\dfrac{350\cdot4\%}{40}=0.35\left(mol\right)\)
\(FeCl_2+2NaOH\rightarrow Fe\left(OH\right)_2+2NaCl\)
\(0.15...........0.3................0.15............0.3\)
\(m_{Fe\left(OH\right)_3}=0.15\cdot90=13.5\left(g\right)\)
\(m_{dd}=150+350-13.5=486.5\left(g\right)\)
\(C\%_{NaCl}=\dfrac{0.3\cdot58.5}{486.5}\cdot100\%=3.61\%\)
\(C\%_{NaOH\left(dư\right)}=\dfrac{\left(0.35-0.3\right)\cdot40}{486.5}\cdot100\%=0.4\%\)
\(Fe\left(OH\right)_2\underrightarrow{^{^{t^0}}}FeO+H_2O\)
\(0.15..........0.15\)
\(m_{FeO}=0.15\cdot72=10.8\left(g\right)\)
\(4Fe\left(OH\right)_2+O_2\underrightarrow{^{^{t^0}}}2Fe_2O_3+4H_2O\)
\(0.15.........................0.075\)
\(m_{Fe_2O_3}=0.075\cdot160=12\left(g\right)\)
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) \(C\%_{ddNaOH}=\dfrac{4.100\%}{50}=8\%\)