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TL:
Sai nhé bạn
Bạn k cho mik cái đi nhé
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HT
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PTHH : 2Al + 6HCl --> 2AlCl3 + 3H2 ↑ (1)
nAlCl3 = \(\dfrac{m}{M}=\dfrac{13,35}{27+35,5.3}=0.1\left(mol\right)\)
Từ (1) => nHCl = 2nH2 = 0.2 (mol)
=> mHCl = n.M = 0.2 x 36.5 = 7.3 (g)
\(PTHH:2Al+6HCl\rightarrow2AlCl_3+3H_2\\ n_{AlCl_3}=\dfrac{m}{M}=\dfrac{13,35}{133,5}=0,1\left(mol\right)\\ Theo.PTHH:n_{HCl}=3.n_{AlCl_3}=3.0,1=0,3\left(mol\right)\\ m_{HCl}=n.M=0,3.36,5=10,95\left(g\right)\)
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a) \(\dfrac{3}{4}+\dfrac{9}{5}\div\dfrac{3}{2}-1=\dfrac{3}{4}+\dfrac{18}{15}-1=\dfrac{39}{20}-1=\dfrac{19}{20}\)
b) \(\dfrac{6}{7}\cdot\dfrac{8}{13}+\dfrac{6}{13}\cdot\dfrac{9}{7}-\dfrac{4}{13}\cdot\dfrac{6}{7}=\dfrac{48}{91}+\dfrac{54}{91}-\dfrac{24}{91}=\dfrac{48+51-24}{91}=\dfrac{78}{91}=\dfrac{6}{7}\)
c) \(\dfrac{-3}{7}+\left(\dfrac{3}{-7}-\dfrac{3}{-5}\right)\)\(=\dfrac{-3}{7}+\left(\dfrac{-3}{7}-\dfrac{-3}{5}\right)=\dfrac{-3}{7}+\dfrac{6}{35}=-\dfrac{9}{35}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(=3\left(x-3y\right)\)
b) \(=5xy\left(3x-2y\right)\)
c) \(=5y\left(x+2y\right)+2\left(x+2y\right)=\left(x+2y\right)\left(5y+2\right)\)
d) \(=\left(9x^2+6x+1\right)-4y^2=\left(3x+1\right)^2-4y^2=\left(3x+1-2y\right)\left(3x+1+2y\right)\)
e) \(=x\left(x+1\right)+3\left(x+1\right)=\left(x+1\right)\left(x+3\right)\)
g) \(=x\left(x-2\right)-\left(x-2\right)=\left(x-2\right)\left(x-1\right)\)
a) \(3x-9y\)
\(=3\left(x-3y\right)\)
b) \(15x^2y-10xy^2\)
\(=5xy\left(3x-2y\right)\)
c) \(5xy+10y^2+2x+4y\)
\(=\left(x+2y\right)\left(5y+2\right)\)
d) \(9x^2-4x^2+6x+1\)
\(=\left(3x+1-2y\right)\left(3x+1+2y\right)\)
e) \(x^2+4x+3\)
\(=\left(x+1\right)\left(x+3\right)\)
d) \(x^2-3x+2\)
\(=\left(x-1\right)\left(x-2\right)\)
![](https://rs.olm.vn/images/avt/0.png?1311)
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b: Gọi giao của AH với BC là F
=>AH vuông góc BC tại F
góic CHI=góc AHD=90 độ-góc HAD=góc ABC=1/2*sđ cung AC
góc CIH=1/2*sđ cung CA
=>góc CHI=góc CIH
=>ΔCHI cân tại C
c:
góc BDC=góc BEC=90 độ
=>BDEC nội tiếp đường tròn đường kính BC
=>MD=ME
=>ΔMDE cân tại M
mà MN là trung tuyến
nên MN vuông góc DE
Kẻ tiếp tuyến Ax của (O)
=>góc xAC=góc ABC
=>góc xAC=góc AED
=>Ax//DE
=>DE vuông góc OA
=>MN//AO
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Rewrite the following sentences with the same meaning od the given ones
1. I bought a new notebook on the way to school (stopped)
→ I stopped on the way to school to buy a new notebook.
2. We're staying in Milan for a night before flying home (planning)
→ We're planning to stay in Milan for a night before flying home.
3. I don't want to cook tonight - let's have a takeaway (feel)
→ I don't feel like cooking tonight - let's have a takeaway.
4. Could you ask Francis to come into my office, please ? (mind)
→ Do you mind asking Francis to come into my office, please?
5. I don't think it's likely that you will win the competition. (chance)
→ There is not much chance that you will win the competition.
6. They'll show Titan at the cinema and they'll release the DVD (before)
→ They will release the DVD before showing Titan at the cinema.
7. I'll finish marking the exam and then I'll tell you your results (soon)
→ Soon, I'll finish marking the exam and then I'll tell you your results.
8. I saw the film and then I read the book (after)
→ After I saw the film, I read the book.
9. My parent wouldn't let me stay out lae when I was young (used to)
→ When I was young, I used to not be allowed to stay out late by my parents.
10. Daren thinks that wearing a suit to work is appropriate (likes)
→ Daren likes to wear a suit to work and thinks it is appropriate.