cho5,6 gam Fe phản ứng hết với 50 gam dd HCl (dư) .Em hãy tính nồng độ % của dd FeCl2
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PT: \(Cu+2AgNO_3\rightarrow Cu\left(NO_3\right)_2+2Ag\)
a, m AgNO3 (pư) = 250.17%.6% = 2,55 (g)
\(\Rightarrow n_{AgNO_3\left(pư\right)}=\dfrac{2,55}{170}=0,015\left(mol\right)\)
Theo PT: nCu (pư) = 1/2nAgNO3 = 0,0075 (mol)
nAg = nAgNO3 = 0,015 (mol)
⇒ m vật lấy ra = 50 - mCu (pư) - mAg = 51,14 (g)
b, Ta có: m dd sau pư = 0,0075.64 + 250 - 0,015.108 = 248,86 (g)
Theo PT: nCu(NO3)2 = 1/2nAgNO3 = 0,0075 (mol)
\(\Rightarrow C\%_{Cu\left(NO_3\right)_2}=\dfrac{0,0075.188}{248,86}.100\%\approx0,57\%\)
\(C\%_{AgNO_3}=\dfrac{250.6\%-2,55}{248,86}.100\%\approx5\%\)
\(SO_3+H_2O\rightarrow H_2SO_4\\ H_2SO_4+Na_2SO_3\rightarrow Na_2SO_4+SO_2+H_2O\\ SO_2+Na_2O\rightarrow Na_2SO_3\\ Na_2SO_3+2HCl\rightarrow2NaCl+SO_2+H_2O\)
1, SO3+H2O->H2SO4
2, H2SO4+Na2SO3->Na2SO4+H2O+SO2
3, SO2+2NaOH->Na2SO3+H2O
4, Na2SO3+H2SO4->Na2SO4+H2O+SO2
\(\left(1\right)3Fe+2O_2\xrightarrow[]{t^0}Fe_3O_4\\ \left(2\right)Fe_3O_4+8HCl\rightarrow2FeCl_3+FeCl_2+4H_2O\\ \left(3\right)FeCl_2+Ag_2SO_4\rightarrow FeSO_4+2AgCl\\ \left(4\right)FeSO_4+Ba\left(NO_3\right)_2\rightarrow Fe\left(NO_3\right)_2+BaSO_4\\ \left(5\right)Fe\left(NO_3\right)_2+2NaOH\rightarrow Fe\left(OH\right)_2+2NaNO_3\\ \left(6\right)Fe\left(OH\right)_2\xrightarrow[]{t^0}FeO+H_2O\)
\(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
PTHH:
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
0,2 0,6 0,2 0,3
\(m_{Al}=0,2.27=5,4\left(g\right)\)
\(C_{M\left(HCl\right)}=\dfrac{0,6}{0,6}=1\left(M\right)\)
\(m_{AlCl_3}=0,2.133,5=26,7\left(g\right)\)
\(a)n_{H_2}=\dfrac{6,72}{22,4}=0,3mol\\ 2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ 0,2\leftarrow-0,3\leftarrow-0,1\leftarrow---0,3\)
\(a=m_{Al}=0,2.27=5,4g\\ b)m_{Al_2\left(SO_4\right)_3}=0,1.342=34,2g\\ c)C_{\%H_2SO_4}=\dfrac{0,3.98}{100}\cdot100=29,4\%\)
a)nH2=22,46,72=0,3mol2Al+3H2SO4→Al2(SO4)3+3H20,2←−0,3←−0,1←−−−0,3
\(Pt: Fe + 2HCl \rightarrow FeCl_2 + H_2\)
\(a.n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)
Theo pt: \(nH_2 = nFe = 0,2 mol\)
\(\Rightarrow V_{H_2}=0,2.22,4=4,48l\)
\(b.n_{FeCl_2}=n_{Fe}=0,2\left(mol\right)\)
\(\Rightarrow m_{FeCl_2}=0,2.127=25.4g\)
\(c.n_{HCl}=2nFe=0,4mol\)
\(C_MHCl=\dfrac{0,4}{0,1}=4M\)
Cho hỗn hợp vào dung dịch NaOH.
Lọc lấy chất rắn không tan thu được sắt
\(2Al+2NaOH+2H_2O\rightarrow2NaAlO_2+3H_2\)
\(Zn+2HCl\rightarrow ZnCl_2+H_2\\ n_{HCl}=0,3.0,15=0,045\left(mol\right)\\ n_{Zn}=n_{H_2}=\dfrac{0,045}{2}=0,0225\left(mol\right)\\ a,m_{Zn}=0,0225.65=1,4625\left(g\right)\\ b,V_{H_2\left(đktc\right)}=22,4.0,0225=0,504\left(l\right)\\ c,n_{Zn}=\dfrac{19,5}{65}=0,3\left(mol\right)\\ Vì:\dfrac{0,3}{1}>\dfrac{0,045}{2}\Rightarrow Zndư\\ \Rightarrow n_{ZnCl_2}=\dfrac{0,045}{2}=0,0225\left(mol\right)\\ m_{ZnCl_2}=0,0225.136=3,06\left(g\right)\)
\(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\\ PTHH:Fe+2HCl\rightarrow FeCl_2+H_2\\ n_{FeCl_2}=n_{H_2}=n_{Fe}=0,1\left(mol\right)\\ m_{ddFeCl_2}=5,6+50-0,1.2=55,4\left(g\right)\\ C\%_{ddFeCl_2}=\dfrac{127.0,1}{55,4}.100\%\approx22,924\%\)