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Theo gt ta có: $n_{HCl}=0,1(mol)$
$Fe+2HCl\rightarrow FeCl_2+H_2$
a, Ta có: $n_{Fe}=0,05(mol)\Rightarrow m_{Fe}=2,8(g)$
b, Ta có: $n_{H_2}=0,05(mol)\Rightarrow V_{H_2}=1,12(l)$
\(n_{HCl}=C_M.V=0,1mol\)
a, \(PTHH:Fe+2HCl\rightarrow FeCl_2+H_2\)
- Theo PTHH : nFe = 0,05mol
=> m = 2,8g
b, - Theo PTHH : nH2 = 0,05mol
=> V = 1,12l
\(n_{H_2SO_4}=0.6\left(mol\right)\)
\(4Fe^{\dfrac{+3}{4}}\rightarrow4Fe^{3+}+9e\)
\(x...................\dfrac{9}{4}x\)
\(S^{+6}+2e\rightarrow S^{+4}\)
\(0.6......1.2\)
Bảo toàn e :
\(\dfrac{9}{4}x=1.2\Rightarrow x=\dfrac{8}{15}\)
\(m=\dfrac{8}{15}\cdot232=123.7\left(g\right)\)
\(n_{Fe}=\frac{5,6}{56}=0,1mol\)
PTHH : Fe + 2HCl \(\rightarrow\) FeCl + H2
(mol) 0,1 0,2 0,1 0,1
\(C_{M_{dd_{HCl}}}=\frac{0,2}{0,5}=0,4mol/l\)
\(C_{M_{dd_{FeCl_2}}}=\frac{0,1}{0,5}=0,2mol/l\)
Câu 1:
Ta có: \(n_{H_2SO_4}=0,25.1=0,25\left(mol\right)\)
PT: \(Na_2CO_3+H_2SO_4\rightarrow Na_2SO_4+H_2O+CO_2\)
\(CaCO_3+H_2SO_4\rightarrow CaSO_4+H_2O+CO_2\)
\(MgCO_3+H_2SO_4\rightarrow MgSO_4+H_2O+CO_2\)
Theo PT, có: \(n_{H_2O}=n_{CO_2}=n_{H_2SO_4}=0,25\left(mol\right)\)
\(\Rightarrow V_{CO_2}=0,25.22,4=5,6\left(l\right)\)
Theo ĐLBT KL, có: mhh + mH2SO4 = m muối + mH2O + mCO2
⇒ m muối = mhh + mH2SO4 - mH2O - mCO2
= 25,2 + 0,25.98 - 0,25.18 - 0,25.44
= 34,2 (g)
Bạn tham khảo nhé!
Câu 2:
Ta có: \(n_{H_2SO_4}=0,5\cdot0,75=0,375\left(mol\right)=n_{H_2O}\)
\(\Rightarrow\left\{{}\begin{matrix}m_{H_2SO_4}=0,375\cdot98=36,75\left(g\right)\\m_{H_2O}=0,375\cdot18=6,75\left(g\right)\end{matrix}\right.\)
Bảo toàn khối lượng: \(m_{oxit}=m_{muối}+m_{H_2O}-m_{H_2SO_4}=28,5\left(g\right)\)
a)
$2Al + 6HCl \to 2AlCl_3 + 3H_2$
$n_{Al} = \dfrac{10,8}{27} = 0,4(mol)$
Theo PTHH : $n_{HCl} = 3n_{Al} = 1,2(mol)$
$\Rightarrow m = \dfrac{1,2.36,5}{14,6\%} = 300(gam)$
b) $n_{H_2} = \dfrac{3}{2}n_{Al} = 0,6(mol)$
$M_xO_y + yH_2 \xrightarrow{t^o}xM + yH_2O$
Theo PTHH : $n_{oxit} = \dfrac{1}{y}.n_{H_2} = \dfrac{0,6}{y}(mol)$
$\Rightarrow \dfrac{0,6}{y}(Mx + 16y) = 34,8$
$\Rightarrow \dfrac{x}{y}.M = 42$
Với x = 3 ; y = 4 thì $M = 56(Fe)$
Vậy oxit là $Fe_3O_4$
Bài 5:
mCu= 43,24% . 14,8\(\approx\) 6,4(g)
=>mFe\(\approx\) 14,8 - 6,4= 8,4(g)
=> nFe\(\approx\) 8,4/56\(\approx\) 0,15(mol)
PTHH: Fe + 2 HCl -> FeCl2 + H2
nH2=nFe \(\approx\) 0,15 (mol)
=> V(H2,đktc) \(\approx\) 0,15 . 22,4\(\approx\) 3,36(l)
Bài 6:
nH2= 4,368/22,4=0,195(mol)
Đặt: nMg=a(mol); nAl=b(mol) (a,b>0)
PTHH: Mg + 2 HCl -> MgCl2 + H2
a________2a_____a_____a(mol)
2 Al + 6 HCl -> 2 AlCl3 +3 H2
b____3b____b______1,5b(mol)
Ta có hpt:
\(\left\{{}\begin{matrix}24a+27b=3,87\\a+1,5b=0,195\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,06\\b=0,09\end{matrix}\right.\)
a) nH2SO4= 2a+3b=0,39(mol)
=> mH2SO4= 0,39.98=38,22(g)
b) m(muối)= mMgSO4 + mAl2(SO4)3= 120a+ 133,5b= 120.0,06+133,5.0,09= 19,215(g)
\(n_{HCl} = 0,5.0,25 = 0,125(mol)\\ Fe + 2HCl \to FeCl_2 + H_2\\ n_{Fe} = \dfrac{1}{2}n_{HCl} = 0,0625(mol)\\ \Rightarrow m = 0,0625.56 = 3,5(gam)\)