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Bài 19 :
\(a) n_{Al} = \dfrac{10,8}{27} = 0,4(mol)\\ 2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2\\ n_{H_2} = \dfrac{3}{2}n_{Al} = 0,6(mol)\\ V_{H_2} = 0,6.22,4 = 13,44(lít)\\ b) \text{Chất tan : }Al_2(SO_4)_3\\ n_{Al_2(SO_4)_3} = \dfrac{1}{2}n_{Al} = 0,2(mol)\\ m_{Al_2(SO_4)_3} = 0,2.342 = 68,4(gam)\)
Bài 18 :
\(a) n_{HCl} = \dfrac{250.7,3\%}{36,5 } = 0,5(mol)\\ Zn + 2HCl \to ZnCl_2 + H_2\\ n_{H_2} = \dfrac{1}{2}n_{HCl} = 0,25(mol) \Rightarrow V_{H_2} = 0,25.22,4 = 5,6(lít)\\ b) \text{Chất tan : } ZnCl_2\\ n_{ZnCl_2} = n_{H_2} = 0,25(mol)\\ m_{ZnCl_2} = 0,25.136 = 34(gam)\)
PTHH: \(BaCl_2+H_2SO_4\rightarrow2HCl+BaSO_4\downarrow\)
a+b) Ta có: \(n_{BaCl_2}=\dfrac{400\cdot5,2\%}{208}=0,1\left(mol\right)=n_{H_2SO_4}=n_{BaSO_4}\)
\(\Rightarrow\left\{{}\begin{matrix}m_{ddH_2SO_4}=\dfrac{0,1\cdot98}{20\%}=49\left(g\right)\\m_{BaSO_4}=0,1\cdot233=23,3\left(g\right)\end{matrix}\right.\)
c) Theo PTHH: \(n_{HCl}=0,2\left(mol\right)\) \(\Rightarrow m_{HCl}=0,2\cdot36,5=7,3\left(g\right)\)
Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{ddBaCl_2}+m_{ddH_2SO_4}-m_{BaSO_4}=425,7\left(g\right)\)
\(\Rightarrow C\%_{HCl}=\dfrac{7,3}{425,7}\cdot100\%\approx1,71\%\)
Bạn xem lại giúp mình , coi đề có bị thiếu gì không nhé
a) $n_{Al} = \dfrac{10,8}{27} = 0,4(mol)$
$2Al + 3H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
$n_{H_2} = \dfrac{3}{2}n_{Al} = 0,6(mol)$
$V_{H_2} =0,6.22,4 = 13,44(lít)$
b) $n_{Al_2(SO_4)_3} = \dfrac{1}{2}n_{Al} = 0,2(mol)$
$m_{Al_2(SO_4)_3} = 0,2.342 =68,4(gam)$
mNaOH = 200.10% = 20 gam ➝ nNaOH = 0,5 mol
nH2SO4 = 0,1 mol, nMgSO4 = 0,2 mol
Phản ứng:
(1) 2NaOH + H2SO4 ➝ Na2SO4 + 2H2O
0,2 0,1 0,1 (mol)
(2) 2NaOH + MgSO4 ➝ Mg(OH)2 + Na2SO4
0,3 0,15 0,15 0,15 (mol)
Dung dịch X: Na2SO4: 0,25 mol, MgSO4 dư: 0,05 mol
Kết tủa Mg(OH)2: 0,15 mol
Mg(OH)2 ➝ MgO + H2O
0,15 0,15
m1 = 0,15.58 = 8,7 gam
m2 = 0,15.40 = 6 gam
PTHH: \(BaCl_2+Na_2SO_4\rightarrow2NaCl+BaSO_4\downarrow\)
Ta có: \(n_{BaCl_2}=\dfrac{200\cdot13,8\%}{208}=\dfrac{69}{520}\left(mol\right)=n_{Na_2SO_4}=n_{BaSO_4}\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{Na_2SO_4}=\dfrac{\dfrac{69}{520}\cdot142}{250}\cdot100\%\approx7,54\%\\m_{BaSO_4}=\dfrac{69}{520}\cdot233\approx30,92\left(g\right)\end{matrix}\right.\)
\(n_{BaCl_2}=\frac{400.5,2\%}{208}=0,1\left(mol\right);n_{H_2SO_4}=\frac{100.1,14.19,6\%}{98}=0,228\left(mol\right)\)
PTHH: \(BaCl_2+H_2SO_4\rightarrow BaSO_4+2HCl\)
Theo đề: 0,1.........0,228.....................................(mol)
Lập tỉ lệ: \(\frac{0,1}{1}< \frac{0,228}{1}\)=> Sau phản ứng H2SO4 dư
Theo PT: \(n_{BaSO_4}=n_{BaCl_2}=0,1\left(mol\right)\)
\(\Rightarrow m_{BaSO_4}=0,1.233=23,3\left(g\right)\)
dd sau khi lọc bỏ kết tủa: H2SO4 dư, HCl
\(m_{ddsaup.ứ}=400+114-23,3=490,7\left(g\right)\)
\(\Rightarrow C\%_{H_2SO_4\left(dư\right)}=\frac{\left(0,228-0,1\right).98}{490,7}.100=2,56\%\)
\(C\%_{HCl}=\frac{0,1.2.36,5}{490,7}.100=1,49\%\)
\(m_{Ba\left(OH\right)_2}=\dfrac{100\cdot17,1\%}{100\%}=17,1\left(g\right)\\ n_{Ba\left(OH\right)_2}=\dfrac{17,1}{171}=0,1\left(mol\right)\\ PTHH:Ba\left(OH\right)_2+2HCl\rightarrow BaCl_2+H_2O\\ n_{BaCl_2}=n_{Ba\left(OH\right)_2}=0,1\left(mol\right)\\ \Rightarrow m_{muối.sau.p/ứ}=m_{BaCl_2}=0,1\cdot208=20,8\left(g\right)\)
a) mBaCl2= 5,2%.400= 20,8(g) ->nBaCl2= 0,1(mol)
PTHH: BaCl2 + H2SO4 -> BaSO4 + 2 HCl
0,1_________0,1______0,1____0,2(mol)
m(kt)=mBaSO4=0,1.233=23,3(g)
b) mHCl=0,2.36,5=7,3(g)
mddHCl= 100+400-23,3= 476,7(g)
=>C%ddHCl=(23,3/476,7).100=4,888%