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![](https://rs.olm.vn/images/avt/0.png?1311)
\(n_{H_2}=\dfrac{0,953m}{22,4}=0,042545m\left(mol\right)\\ Đặt:n_{Mg}=x\left(mol\right);n_{Al}=y\left(mol\right);n_{Cu}=z\left(mol\right)\left(x,y,z>0\right)\\\Rightarrow \left\{{}\begin{matrix}24x+27y+64z=m\\40x+51y+80z=1,72m\\x+1,5y=0,042545m\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x\approx0,012845m\\y\approx0,0198m\\z\approx0,002455m\end{matrix}\right.\\ \Rightarrow\%m_{Cu}\approx\dfrac{0,002455.64m}{m}.100\%\approx15,712\%\\ \%m_{Al}\approx\dfrac{27.0,0198m}{m}.100\%\approx53,46\%\\ \%m_{Mg}\approx\dfrac{0,012845.24m}{m}.100\%\approx30,828\%\)
![](https://rs.olm.vn/images/avt/0.png?1311)
PTHH: \(2Mg+O_2\underrightarrow{t^o}2MgO\) (1)
\(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\) (2)
a) Gọi số mol của Mg là a (mol) \(\Rightarrow n_{Al}=\dfrac{2}{3}a\left(mol\right)\)
\(\Rightarrow24a+27\cdot\dfrac{2}{3}a=6,3\) \(\Rightarrow a=0,15\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{MgO}=0,15\left(mol\right)\\n_{Al_2O_3}=0,05\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{MgO}=0,15\cdot40=6\left(g\right)\\m_{Al_2O_3}=0,05\cdot102=5,1\left(g\right)\end{matrix}\right.\)
b) Theo các PTHH: \(\left\{{}\begin{matrix}n_{O_2\left(1\right)}=0,075\left(mol\right)\\n_{O_2\left(2\right)}=0,075\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\Sigma n_{O_2}=0,15\left(mol\right)\) \(\Rightarrow V_{O_2}=0,15\cdot22,4=3,36\left(l\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Gọi số mol Al, Na trong a gam hỗn hợp là x, y (mol)
=> 27x + 23y = a (1)
PTHH: 4Al + 3O2 --to--> 2Al2O3
x---------------->0,5x
4Na + O2 --to--> 2Na2O
y---------------->0,5y
=> 102.0,5x + 62.0,5y = 1,64.a
=> 51x + 31y = 1,64a (2)
(1)(2) => 51x + 31y = 1,64(27x + 23y)
=> 6,72x = 6,72y
=> x = y
\(\left\{{}\begin{matrix}\%m_{Al}=\dfrac{27x}{27x+23y}.100\%=54\%\\\%m_{Na}=\dfrac{23y}{27x+23y}.100\%=46\%\end{matrix}\right.\)
![](https://rs.olm.vn/images/avt/0.png?1311)
PTHH:
\(CuO+H_2\) \(\underrightarrow{t^o}\) \(Cu+H_2O\) \(\left(1\right)\)
\(Fe_2O_3+3H_2\) \(\underrightarrow{t^o}\) \(2Fe+3H_2O\) \(\left(2\right)\)
Số mol H2 là 0,6 mol
Gọi số mol H2 tham gia pư 1 là x mol \(\left(0,6>x>0\right)\)
Số mol H2 tham gia pư 2 là \(\left(0,6-x\right)mol\)
Theo PTHH 1:
\(n_{CuO}=n_{H_2}=x\left(mol\right)\)
Theo PTHH 2:
\(n_{Fe_2O_3}=\frac{1}{3}n_{H_2}=\left(0,6-x\right):3\left(mol\right)\)
Theo bài khối lượng hh là 40g
Ta có pt: \(80x+\left(0,6-x\right)160:3=40\)
Giải pt ta được \(x=0,3\)
Vậy \(n_{CuO}=0,3\left(mol\right);n_{Fe_2O_3}=0,1\left(mol\right)\)
\(\%m_{CuO}=\left(0,3.80.100\right):40=60\%\)
\(\%m_{Fe_2O_3}=\left(0,1.160.100\right):40=40\%\)
1)
PTHH: \(2Cu+O_2\) \(\underrightarrow{t^o}\) \(2CuO\)
x x
Gọi số mol Cu phản ứng là x mol ( x >0)
Chất rắn X gồm CuO và Cu
Ta có PT: 80x + 25,6 – 64x = 28,8
Giải PT ta được x = 0,2
Vậy khối lượng các chất trong X là:
\(m_{Cu}\) = 12,8 gam
\(m_{CuO}\) = 16 gam
2)
Gọi kim loại hoá trị II là A.
PTHH: \(A+2HCl\rightarrow ACl_2+H_2\)
Số mol \(H_2\)= 0,1 mol
Theo PTHH: \(n_A=n_{H_2}\)= 0,1 (mol)
Theo bài \(m_A\) = 2,4 gam \(\Rightarrow\) \(M_A\) = 2,4 : 0,1 = 24 gam
Vậy kim loại hoá trị II là Mg
![](https://rs.olm.vn/images/avt/0.png?1311)
\(a,n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
PTHH: Ba + 2H2O ---> Ba(OH)2 + H2
0,3<-------------0,3<---------0,3
=> mBa = 0,3.137 = 41,1 (g)
=> mK2O = 59,9 - 41,1 = 18,8 (g)
\(\rightarrow\left\{{}\begin{matrix}\%m_{Ba}=\dfrac{41,1}{59,9}.100\%=68,61\%\\\%m_{K_2O}=100\%-68,61\%=31,39\%\end{matrix}\right.\)
\(b,n_{K_2O}=\dfrac{18,8}{94}=0,2\left(mol\right)\)
PTHH: K2O + H2O ---> 2KOH
0,2----------------->0,4
Các chất tan trong dd sau phản ứng: KOH, Ba(OH)2
\(\rightarrow\left\{{}\begin{matrix}m_{KOH}=0,4.56=22,4\left(g\right)\\m_{Ba\left(OH\right)_2}=0,3.171=51,3\left(g\right)\end{matrix}\right.\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Theo ĐLBT KL, có: mKL + mO2 = m oxit
⇒ mO2 = 13,1 - 1,5 = 11,6 (g)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Do dd sau pư có 3 chát tan với nồng độ % bằng nhau
=> \(m_{Al_2\left(SO_4\right)_3}=m_{ZnSO_4}=m_{H_2SO_4\left(dư\right)}\)
Gọi số mol Al, Zn là a, b (mol)
PTHH: 2Al + 3H2SO4 --> Al2(SO4)3 + 3H2
a----->1,5a------->0,5a----->1,5a
Zn + H2SO4 --> ZnSO4 + H2
b----->b--------->b----->b
=> \(\left\{{}\begin{matrix}m_{Al_2\left(SO_4\right)_3}=342.0,5a=171a\left(g\right)\\m_{ZnSO_4}=161b\left(g\right)\end{matrix}\right.\)
=> 171a = 161b
=> \(\dfrac{a}{b}=\dfrac{161}{171}\) (1)
Có: \(\dfrac{m_{Al}}{m_{Zn}}=\dfrac{27.n_{Al}}{65.n_{Zn}}=\dfrac{27}{65}.\dfrac{161}{171}=\dfrac{483}{1235}\)
b) \(n_{H_2}=1,5a+b=\dfrac{11,2}{22,4}=0,5\left(mol\right)\) (2)
(1)(2) => \(\left\{{}\begin{matrix}a=\dfrac{161}{825}\left(mol\right)\\b=\dfrac{57}{275}\left(mol\right)\end{matrix}\right.\)
=> \(x=\dfrac{161}{825}.27+\dfrac{57}{275}.65=\dfrac{5154}{275}\left(g\right)\)
\(m_{H_2SO_4\left(dư\right)}=m_{Al_2\left(SO_4\right)_3}=342.0,5\dfrac{161}{825}=\dfrac{9177}{275}\left(g\right)\)
=> \(m_{H_2SO_4\left(bđ\right)}=98\left(1,5a+b\right)+\dfrac{9177}{275}=\dfrac{22652}{275}\left(g\right)\)
=> \(y=\dfrac{\dfrac{22652}{275}.100}{10}=\dfrac{45304}{55}\left(g\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Do dd sau pư có 3 chát tan với nồng độ % bằng nhau
=> \(m_{Al_2\left(SO_4\right)_3}=m_{ZnSO_4}=m_{H_2SO_4\left(dư\right)}\)
Gọi số mol Al, Zn là a, b (mol)
PTHH: 2Al + 3H2SO4 --> Al2(SO4)3 + 3H2
a----->1,5a------->0,5a----->1,5a
Zn + H2SO4 --> ZnSO4 + H2
b----->b--------->b----->b
=> \(\left\{{}\begin{matrix}m_{Al_2\left(SO_4\right)_3}=342.0,5a=171a\left(g\right)\\m_{ZnSO_4}=161b\left(g\right)\end{matrix}\right.\)
=> 171a = 161b
=> \(\dfrac{a}{b}=\dfrac{161}{171}\) (1)
Có: \(\dfrac{m_{Al}}{m_{Zn}}=\dfrac{27.n_{Al}}{65.n_{Zn}}=\dfrac{27}{65}.\dfrac{161}{171}=\dfrac{483}{1235}\)
b) \(n_{H_2}=1,5a+b=\dfrac{11,2}{22,4}=0,5\left(mol\right)\) (2)
(1)(2) => \(\left\{{}\begin{matrix}a=\dfrac{161}{825}\left(mol\right)\\b=\dfrac{57}{275}\left(mol\right)\end{matrix}\right.\)
=> \(x=\dfrac{161}{825}.27+\dfrac{57}{275}.65=\dfrac{5154}{275}\left(g\right)\)
\(m_{H_2SO_4\left(dư\right)}=m_{Al_2\left(SO_4\right)_3}=342.0,5\dfrac{161}{825}=\dfrac{9177}{275}\left(g\right)\)
=> \(m_{H_2SO_4\left(bđ\right)}=98\left(1,5a+b\right)+\dfrac{9177}{275}=\dfrac{22652}{275}\left(g\right)\)
=> \(y=\dfrac{\dfrac{22652}{275}.100}{10}=\dfrac{45304}{55}\left(g\right)\)
a, PT: \(2Cu+O_2\underrightarrow{t^o}2CuO\)
\(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
\(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
\(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
\(Fe_3O_4+4H_2\underrightarrow{t^o}3Fe+4H_2O\)
Gọi: \(\left\{{}\begin{matrix}n_{Cu}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\\n_{Al}=z\left(mol\right)\end{matrix}\right.\) ⇒ 64x + 56y + 27z = 40,4 (1)
Theo PT: \(\left\{{}\begin{matrix}n_{CuO}=n_{Cu}=x\left(mol\right)\\n_{Fe_3O_4}=\dfrac{1}{3}n_{Fe}=\dfrac{1}{3}y\left(mol\right)\\n_{Al_2O_3}=\dfrac{1}{2}n_{Al}=\dfrac{1}{2}z\left(mol\right)\end{matrix}\right.\)
⇒ 80x + 232.1/3x + 102.1/2z = 59,6 (2)
- Chất rắn A gồm: Cu, Fe và Al3O3.
⇒ 64x + 56y + 102.1/2z = 50 (3)
Từ (1), (2) và (3) \(\Rightarrow\left\{{}\begin{matrix}x=0,2\left(mol\right)\\y=0,3\left(mol\right)\\z=0,4\left(mol\right)\end{matrix}\right.\)
⇒ mCu = 0,2.64 = 12,8 (g)
mFe = 0,3.56 = 16,8 (g)
mAl = 0,4.27 = 10,8 (g)
b, Theo PT: \(n_{H_2}=n_{Cu}+\dfrac{4}{3}n_{Fe}=0,6\left(mol\right)\)
\(\Rightarrow V_{H_2}=0,6.22,4=13,44\left(l\right)\)
mình cũng làm cách giống bạn nhưng thầy bảo mình làm sai:/