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PTHH: \(Mg+H_2SO_4\rightarrow MgsO_4+H_2\uparrow\)
Ta có: \(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)=n_{MgSO_4}=n_{H_2SO_4}\) \(\Rightarrow\left\{{}\begin{matrix}m_{MgSO_4}=0,2\cdot120=24\left(g\right)\\V_{H_2}=0,2\cdot22,4=4,48\left(l\right)\\C\%_{H_2SO_4}=\dfrac{0,2\cdot98}{294}\cdot100\%\approx6,67\%\end{matrix}\right.\)
Câu 1:
PTHH: 2Al + 3H2SO4 ===> Al2(SO4)3 + 3H2
a)Vì Cu không phản ứng với H2SO4 loãng nên 6,72 lít khí là sản phẩm của Al tác dụng với H2SO4
=> nH2 = 6,72 / 22,4 = 0,2 (mol)
=> nAl = 0,2 (mol)
=> mAl = 0,2 x 27 = 5,4 gam
=> mCu = 10 - 5,4 = 4,6 gam
b) nH2SO4 = nH2 = 0,3 mol
=> mH2SO4 = 0,3 x 98 = 29,4 gam
=> Khối lượng dung dịch H2SO4 20% cần dùng là:
mdung dịch H2SO4 20% = \(\frac{29,4.100}{20}=147\left(gam\right)\)
nH2 = 6.72 : 22.4 = 0.3 mol
Cu không tác dụng với H2SO4
2Al + 3H2SO4 -> Al2(SO4)3 + 3H2
0.2 <- 0.3 <- 0.1 <- 0.3 ( mol )
mAl = 0.2 x 56 = 5.4 (g)
mCu = 10 - 5.4 = 4.6 (g )
mH2SO4 = 0.3 x 98 = 29.4 ( g)
mH2SO4 20% = ( 29.4 x100 ) : 20 = 147 (g)
a, \(Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O\)
\(FeCl_3+3KOH\rightarrow3KCl+Fe\left(OH\right)_{3\downarrow}\)
\(n_{Fe_2O_3}=\dfrac{16}{160}=0,1\left(mol\right)\)
Theo PT: \(n_{HCl}=6n_{Fe_2O_3}=0,6\left(mol\right)\)
\(\Rightarrow m_{HCl}=0,6.36,5=21,9\left(g\right)\)
b, \(n_{Fe\left(OH\right)_3}=n_{FeCl_3}=2n_{Fe_2O_3}=0,2\left(mol\right)\)
\(\Rightarrow m_{Fe\left(OH\right)_3}=0,2.107=21,4\left(g\right)\)
\(n_{KOH}=3n_{FeCl_3}=0,6\left(mol\right)\)
\(\Rightarrow C_{M_{KOH}}=\dfrac{0,6}{0,2}=3\left(M\right)\)
\(n_{CuSO_4}=1.0,01=0,01(mol)\\ PTHH:Fe+CuSO_4\to FeSO_4+Cu\)
Do Cu ko td với HCl nên chất rắn sau phản ứng vẫn là Cu
\(n_{Cu}=n_{Fe}=0,01(mol)\\ \Rightarrow m_{Cu}=0,01.64=0,64(g)\\ b,PTHH:FeSO_4+2NaOH\to Fe(OH)_2\downarrow+Na_2SO_4\\ \Rightarrow n_{NaOH}=2n_{FeSO_4}=2n_{Fe}=0,02(mol)\\ \Rightarrow V_{dd_{NaOH}}=0,02.1=0,02(l)\)
a/ Fe + 2HCl \(\rightarrow\) FeCl2 + H2
nH2 = \(\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
Theo PTHH: nH2 = nFe = 0,15 (mol) \(\Rightarrow m_{Fe}=0,15.56=8,4\left(g\right)\)
\(\Rightarrow m_{Cu}=11-8,4=2,6\left(g\right)\)
\(\Rightarrow\%m_{Fe}=\dfrac{8,4}{11}.100\%\approx76,4\%\)
\(\Rightarrow\%m_{Cu}=100-76,4\approx23,6\%\)
b/ Theo PTHH ta có: nHCl = 2nFe = 2.0,15 = 0,3 (mol)
\(\Rightarrow V_{ddHCl}=\dfrac{0,3}{2}=0,15\left(M\right)\)
c/ mHCl = 36,5 . 0,3 = 10,95(g)
\(\Rightarrow C\%_{HCl}=\dfrac{m_{HCl}}{m_{ddHCl}}.100\%=\dfrac{10,95}{200}.100\%=5,475\%\)
a, PT: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
Ta có: \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
Theo PT: \(n_{Fe}=n_{H_2}=0,15\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{0,15.56}{11}.100\%\approx76,36\%\\\%m_{Cu}\approx23,64\%\end{matrix}\right.\)
b, Theo PT: \(n_{HCl}=2n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow V_{ddHCl}=\dfrac{0,3}{2}=0,15\left(l\right)\)
c, \(C\%_{HCl}=\dfrac{0,3.36,5}{200}.100\%=5,475\%\)
a, \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, \(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
Theo PT: \(n_{Zn}=n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow m_{Zn}=0,3.65=19,5\left(g\right)\)
c, \(n_{HCl}=2n_{H_2}=0,6\left(mol\right)\)
\(\Rightarrow C_{M_{HCl}}=\dfrac{0,6}{0,1}=6\left(M\right)\)
Mg + 2HCl → MgCl2 + H2↑ (1)
\(n_{Mg}=\dfrac{2,4}{24}=0,1\left(mol\right)\)
a) theo pT1: \(n_{H_2}=n_{Mg}=0,1\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,1\times22,4=2,24\left(l\right)\)
b) Theo pT1: \(n_{HCl}=2n_{Mg}=2\times0,1=0,2\left(mol\right)\)
\(\Rightarrow m_{HCl}=0,2\times36,5=7,3\left(g\right)\)
\(\Rightarrow m_{ddHCl}=\dfrac{7,3}{10\%}=73\left(g\right)\)
3) \(m_{dd}saupư=2,4+73-\left(0,1\times2\right)=75,2\left(g\right)\)
Theo PT1: \(n_{MgCl_2}=n_{Mg}=0,1\left(mol\right)\)
\(\Rightarrow m_{MgCl_2}=0,1\times95=9,5\left(g\right)\)
\(\Rightarrow C\%_{MgCl_2}=\dfrac{9,5}{75,2}\times100\%=12,63\%\)
4) \(m_{ddAgNO_3}=500\times1,19=595\left(g\right)\)
\(\Rightarrow m_{AgNO_3}=595\times20\%=119\left(g\right)\)
\(\Rightarrow n_{AgNO_3}=\dfrac{119}{170}=0,7\left(mol\right)\)
PTHH: MgCl2 + 2AgNO3 → Mg(NO3)2 + 2AgCl↓ (2)
ban đầu: 0,1.............0,7......................................................(mol)
Phản ứng: 0,1............0,2......................................................(mol)
Sau phản ứng: 0...............0,5..........→.....0,1....................0,2.....(mol)
\(m_{AgCl}=0,2\times143,5=28,7\left(g\right)\)