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a) $2Al +3 H_2SO_4 \to Al_2(SO_4)_3 + 3H_2$
b) $n_{H_2} = \dfrac{4,48}{22,4} = 0,2(mol)$
$n_{Al} = \dfrac{2}{3}n_{H_2} = \dfrac{0,4}{3}(mol)$
$m_{Al} = \dfrac{0,4}{3}.27 = 3,6(gam)$
c) $2H_2 + O_2 \xrightarrow{t^o} 2H_2O$
Theo PTHH : $V_{O_2} = \dfrac{1}{2}V_{H_2} = 2,24(lít)$
$V_{không\ khí} = V_{O_2} : 21\% = 2,24 : 21\% = 10,67(lít)$
a) PTHH: `2Al + 3H_2SO_4 -> Al_2(SO_4)_3`
b) $n_{H_2} = \dfrac{4,48}{22,4} = 0,2 (mol)$
Theo PTHH: $n_{Al} = \dfrac{2}{3} n_{H_2} = \dfrac{2}{15} (mol)$
`=> m_{Al} = 2/(15) . 27 = 3,6 (g)`
c) PTHH: $2H_2 + O_2 \xrightarrow{t^o} 2H_2O$
Theo PTHH: $n_{O_2} = \dfrac{1}{2} n_{H_2} = 0,1 (mol)$
$\rightarrow V_{kk} = \dfrac{0,1.22,4.100}{21} = \dfrac{64}{3} (l)$
a) $Mg + 2HCl \to MgCl_2 + H_2$
b) Theo PTHH : $n_{Mg} = n_{H_2} = \dfrac{6,72}{22,4} = 0,3(mol)$
$m_{Mg} = 0,3.24 = 7,2(gam)$
c) $n_{MgCl_2} = n_{H_2} = 0,3(mol)$
$m_{MgCl_2} = 0,3.95 = 28,5(gam)$
d) $n_{Fe_2O_3} = \dfrac{24}{160} = 0,15(mol)$
$Fe_2O_3 + 3H_2 \xrightarrow{t^o} 2Fe + 3H_2O$
Ta thấy :
$n_{Fe_2O_3} : 1 > n_{H_2} : 3$ nên $Fe_2O_3$ dư
$n_{Fe_2O_3\ pư} = \dfrac{1}{3}n_{H_2} = 0,1(mol)$
$m_{Fe_2O_3\ dư} = 24 - 0,1.160 = 8(gam)$
a) PTHH: Mg + 2HCl ---> MgCl2 + H2
b) \(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
Theo PTHH: \(n_{Mg}=n_{MgCl_2}=n_{H_2}=0,3\left(mol\right)\)
=> mMg = 0,3.24 = 7,2 (g)
c) mmuối = 0,3.95 = 28,5 (g)
d) \(n_{Fe_2O_3}=\dfrac{24}{160}=0,15\left(mol\right)\)
PTHH: \(Fe_2O_3+3H_2\xrightarrow[]{t^o}2Fe+3H_2O\)
Xét tỉ lệ: \(\dfrac{0,15}{1}>\dfrac{0,3}{3}\) => Fe2O3 dư, H2 hết
Theo PTHH: \(n_{Fe_2O_3\left(pư\right)}=\dfrac{1}{3}n_{H_2}=0,1\left(mol\right)\)
=> mFe2O3 dư = (0,15 - 0,1).160 = 8 (g)
a) $Fe + 2HCl \to FeCl_2 + H_2$
Theo PTHH : $n_{H_2} = n_{Fe} = \dfrac{8,4}{56} = 0,15(mol)$
$V_{H_2} = 0,15.22,4 = 3,36(lít)$
b) $n_{FeCl_2} = n_{Fe} = 0,15(mol)$
$m_{FeCl_2} = 0,15.127 = 19,05(gam)$
c) $n_{CuO} = \dfrac{8}{80} = 0,1(mol)$
$CuO + H_2 \xrightarrow{t^o} Cu + H_2O$
$n_{CuO} : 1 < n_{H_2} : 1$ nên $H_2$ dư
$n_{Cu} = n_{CuO} = 0,1(mol)$
$m_{Cu} = 0,1.64 = 6,4(gam)$
a) \(n_{Fe}=\dfrac{8,4}{56}=0,15\left(mol\right)\)
PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
0,15-------------->0,15---->0,15
=> \(V_{H_2}=0,15.22,4=3,36\left(l\right)\)
b) \(m_{muối}=0,15.127=19,05\left(g\right)\)
c) \(n_{CuO}=\dfrac{8}{80}=0,1\left(mol\right)\)
PTHH: \(CuO+H_2\xrightarrow[]{t^o}Cu+H_2O\)
Xét tỉ lệ: \(\dfrac{0,1}{1}< \dfrac{0,15}{1}\) => CuO phản ứng hết, H2 còn dư
Theo PTHH: \(n_{Cu}=n_{CuO}=0,1\left(mol\right)\)
=> mCu = 0,1.64 = 6,4 (g)
Câu 1:
\(H_2SO_4\left\{{}\begin{matrix}p=2p_H+p_S+4p_O=2.1+16+4.8=50\\e=p=50\\n=2n_H+n_S+4.n_O=2.1+16+8.4=50\end{matrix}\right.\)
\(Na_3PO_4\left\{{}\begin{matrix}p=3p_{Na}+p_P+4p_O=3.11+15+4.8=80\\e=p=80\\n=3n_{Na}+n_P+4n_O=84\end{matrix}\right.\)
a) $Fe + CuSO_4 \to FeSO_4 + Cu$
b) Gọi $n_{CuSO_4} = a(mol)$
Theo PTHH : $n_{Fe} = n_{Cu} = n_{CuSO_4} = a(mol)$
$m_{chất\ rắn\ sau\ pư} = m_{lá\ sắt} - m_{Fe\ pư} + m_{Cu}$
$\Rightarrow 5,16 = 5 - 56a + 64a$
$\Rightarrow a = 0,02$
$n_{FeSO_4} = 0,02(mol) \Rightarrow C_{M_{FeSO_4}} = \dfrac{0,02}{0,15} = 0,13M$