1. Hoà tan 11,2g Fe vào 200ml dd Hcl 2,5M.
a. Tính V khí H2 thoát ra (đktc)
b. Tính CM của dd thu được? (Bỏ qua thể tích của chất rắn khi hoà tan)?
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\(a)n_{H_2}=\dfrac{2,24}{22,4}=0,1mol\\
Fe+2HCl\rightarrow FeCl_2+H_2\)
0,1 0,2 0,1 0,1
\(n_{Fe_2O_3}=\dfrac{21,6-56.0,1}{160}=0,1mol\\
Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2\)
0,1 0,6 0,2 0,3
\(V_{ddHCl}=\dfrac{0,2+0,6}{1}=0,8l\\
b.C_{M_{FeCl_2}}=\dfrac{0,1}{0,8}=0,125M\\
C_{M_{FeCl_3}}=\dfrac{0,2}{0,8}=0,25M\)
`1)`
`n_{Al}={2,7}/{27}=0,1(mol)`
`2Al+3H_2SO_4->Al_2(SO_4)_3+3H_2`
`0,1->0,15->0,05->0,15(mol)`
`V_{dd\ H_2SO_4}={0,15}/1=0,15(l)=150(ml)`
`->V=150`
`V'=V_{H_2}=0,15.22,4=3,36(l)`
`C_{M\ X}=C_{M\ Al_2(SO_4)_3}={0,05}/{0,15}=1/3M`
`2)`
`n_{Fe}={2,8}/{56}=0,05(mol)`
`Fe+2HCl->FeCl_2+H_2`
`0,05->0,1->0,05->0,05(mol)`
`V_{dd\ HCl}={0,1}/1=0,1(l)=100(ml)`
`->V=100`
`V_{H_2}=0,05.22,4=1,12(l)`
`C_{M\ FeCl_2}={0,05}/{0,1}=0,5M`
\(n_{Al} = a\ ; n_{Fe} =b\\ \Rightarrow 27a + 56b = 11(1)\\ 2Al + 6HCl \to 2AlCl_3 + 3H_2\\ Fe + 2HCl \to FeCl_2 + H_2\\ n_{H_2} = 1,5a + b = \dfrac{8,96}{22,4} = 0,4(2)\\ (1)(2) \Rightarrow a = 0,2 ; b = 0,1\\ n_{HCl\ dư} = \dfrac{200.21,9\%}{36,5} - 0,2.3 - 0,1.2 = 0,4(mol)\\ m_{dd\ sau\ pư} = 11 + 200 - 0,4.2 = 210,2(gam)\\ C\%_{HCl} = \dfrac{0,4.36,5}{210,2}.100\% = 6,95\%\\ \)
\(C\%_{AlCl_3} = \dfrac{0,2.133,5}{210,2}.100\% = 12,7\%\\ C\%_{FeCl_2} = \dfrac{0,1.127}{210,2}.100\% = 6,04\%\)
a, \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
b, \(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)
Theo PT: \(n_{H_2SO_4}=n_{Fe}=0,2\left(mol\right)\Rightarrow m_{H_2SO_4}=0,2.98=19,6\left(g\right)\)
c, \(C\%_{H_2SO_4}=\dfrac{19,6}{50}.100\%=39,2\%\)
d, Theo PT: \(n_{H_2}=n_{Fe}=0,2\left(mol\right)\Rightarrow V_{H_2}=0,2.22,4=4,48\left(l\right)\)
\(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\)
\(Mg+2HCl\rightarrow MgCl_2+H_2\)
0,2-->0,4----->0,2------->0,2
a
\(V_{H_2}=0,2.22,4=4,48\left(l\right)\)
b
\(CM_{MgCl_2}=\dfrac{0,2}{0,2}=1M\)
c
\(MgCl_2+2NaOH\rightarrow Mg\left(OH\right)_2+2NaCl\)
0,2------>0,4
\(V_{dd.NaOH}=\dfrac{0,4}{2}=0,2\left(l\right)\)
CTHH: FexOy
\(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
PTHH: FexOy + yH2 --to--> xFe + yH2O
\(\dfrac{0,2}{x}\)<---------------0,2
Fe + 2HCl --> FeCl2 + H2
0,2<-------------------0,2
=> \(M_{Fe_xO_y}=56x+16y=\dfrac{16}{\dfrac{0,2}{x}}=80x\)
=> \(\dfrac{x}{y}=\dfrac{2}{3}\) => CTHH: Fe2O3
Bài 1: Ta có: \(n_{H_2}=\dfrac{1,008}{22,4}=0,045\left(mol\right)\)
PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)
__0,045__0,09____0,045___0,045 (mol)
a, Ta có: \(a=m_{Mg}=0,045.24=1,08\left(g\right)\)
b, \(V_{ddHCl}=\dfrac{0,09}{0,1}=0,9\left(l\right)\)
c, \(C_{M_{MgCl_2}}=\dfrac{0,045}{0,9}=0,05M\)
Bài 2:
PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
a, Giả sử: \(\left\{{}\begin{matrix}n_{Mg}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\end{matrix}\right.\)
⇒ 24x + 56y = 5,2 (1)
Ta có: \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
Theo PT: \(n_{H_2}=n_{Mg}+n_{Fe}=x+y\left(mol\right)\)
⇒ x + y = 0,15 (2)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,1\left(mol\right)\\y=0,05\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Mg}=\dfrac{0,1.24}{5,2}.100\%\approx46,2\%\\\%m_{Fe}\approx53,8\%\end{matrix}\right.\)
b, Ta có: \(n_{HCl}=2n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow V_{HCl}=\dfrac{0,3}{1}=0,3\left(l\right)\)
Bạn tham khảo nhé!
\(n_{Zn}=\dfrac{6,5}{65}=0,1\left(mol\right)\)
PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
Theo PT: \(n_{H_2}=n_{Zn}=0,1\left(mol\right)\Rightarrow V_{H_2}=0,1.22,4=2,24\left(l\right)\)
\(n_{ZnCl_2}=n_{Zn}=0,1\left(mol\right)\Rightarrow C_{M_{ZnCl_2}}=\dfrac{0,1}{0,2}=0,5\left(M\right)\)
a, Ta có: \(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)
PT: \(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
Theo PT: \(n_{FeSO_4}=n_{Fe}=0,1\left(mol\right)\Rightarrow m_{FeSO_4}=0,1.152=15,2\left(g\right)\)
b, \(n_{H_2}=n_{Fe}=0,1\left(mol\right)\Rightarrow V_{H_2}=0,1.22,4=2,24\left(l\right)\)
c, Sửa đề: 500 ml → 500 (g)
Theo PT: \(n_{H_2SO_4}=n_{Fe}=0,1\left(mol\right)\Rightarrow C\%_{H_2SO_4}=\dfrac{0,1.98}{500}.100\%=1,96\%\)
\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right);n_{HCl}=0,2.2,5=0,5\left(mol\right)\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ Vì:\dfrac{0,2}{1}< \dfrac{0,5}{2}\Rightarrow HCl.dư\\ n_{H_2}=n_{FeCl_2}=n_{Fe}=0,2\left(mol\right);n_{HCl\left(dư\right)}=0,5-0,2.2=0,1\left(mol\right)\\ a,V_{H_2\left(đktc\right)}=0,2.22,4=4,48\left(l\right)\\ b,V_{ddsau}=V_{ddHCl}=0,2\left(l\right)\\ C_{MddFeCl_2}=\dfrac{0,2}{0,2}=1\left(M\right);C_{MddHCl\left(dư\right)}=\dfrac{0,1}{0,2}=0,5\left(M\right)\)