PTHH: \(Al_2O_3+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2O\)

Ta có: \(\left\{{}\begin{matrix}m_{H_2SO_4}=588\cdot5\%=29,4\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{29,4}{98}=0,3\left(mol\right)\\n_{Al_2O_3}=\dfrac{20,4}{102}=0,2\left(mol\right)\end{matrix}\right.\)

Xét tỉ lệ: \(\dfrac{0,2}{1}>\dfrac{0,3}{3}\) \(\Rightarrow\) Al₂O₃ còn dư

\(\Rightarrow n_{Al_2\left(SO_4\right)_3}=0,1\left(mol\right)=n_{Al_2O_3\left(dư\right)}\)

\(\Rightarrow C\%_{Al_2\left(SO_4\right)_3}=\dfrac{0,1\cdot342}{20,4+588-0,1\cdot102}\cdot100\%\approx5,72\%\)

1. Minh used to ____________his homework late in the evening.

A. does                    B. do                             C. doing                    D. did

2. It is not _____________to pass the red traffic light.

A. dangerous               B. safe                    C. safety               D. danger

3. There are many _____________on the street: cars, buses, bikes, motorbikes…

A. vehicles                 B. transport              C. engines           D. machines

4. She spent all day _____________with her children.

A. play                  B. to play                   C. played              D. playing

5. The central square is______________. It is full of people and noise.

A. quiet                  B. peaceful                  C. crowded           D. calm

6. Your behavior is_______________. You should not be rude.

A. disappointing             B. disappointed              

C. disappoint                  D. disappoints

7. If we walk, we should go on the___________.

A. street                 B. pavement                 C. traffic light         D. road

8. “One-way street”, “No parking” are___________.

A. road signs               B. means of transport     

C. traffic rules              D. mistakes

9. He sings___________. Nobody wants to listen to his voice.

A. bad                       B. badly                      C. well                  D. good

10. He runs ___________than me.

A. more faster              B. more fastly            C. more fast          D. faster

\(d,ĐK:x\ge1\\ PT\Leftrightarrow\sqrt{x-1}=2+\sqrt{x+1}\\ \Leftrightarrow x-1=2+x+1+4\sqrt{x+1}\\ \Leftrightarrow4\sqrt{x+1}=-4\Leftrightarrow x\in\varnothing\left(4\sqrt{x+1}\ge0\right)\\ g,ĐK:x\ge\dfrac{1}{2}\\ PT\Leftrightarrow x+\sqrt{2x-1}+x-\sqrt{2x-1}+2\sqrt{\left(x+\sqrt{2x-1}\right)\left(x-\sqrt{2x-1}\right)}=2\\ \Leftrightarrow2x+2\sqrt{x^2-2x+1}=2\\ \Leftrightarrow\sqrt{\left(x-1\right)^2}=\dfrac{2-2x}{2}=1-x\\ \Leftrightarrow\left|x-1\right|=1-x\\ \Leftrightarrow\left[{}\begin{matrix}x-1=1-x\left(x\ge1\right)\\x-1=x-1\left(x< 1\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\left(tm\right)\\x\in R\end{matrix}\right.\)

I. Choose the best answer

1. I wish we ______ shopping together.

A. will go

B. would go

C. go

D. to go

2. The book ______ consists of four parts has been translated into French.

A. which

B. what

C. who

D. whose

3. The national ______ of Malaysia is Malay.

A. language

B. currency

C. religion

D. climate

4. Your mother can speak French fluently, _______?

A. is she

B. can she

C. can’t she

D. doesn’t she

5. I was born ______ September 10th, 1996.

A. in

B. on

C. at

D. from

6. Travelling by air is not cheap and it isn’t interesting ______.

A. either

B. neither

C. too

D. also

7. Young people enjoy ______ computer games.

A. playing

B. play

C. played

D. to play

1. B
2. A
3. A
4. C
5. B
6. A
7. A

I. Choose one sentence that best rewrites the sentence given:

1.      They understand more than we do.

A.    We don’t understand as much as they do.

B.    We  don’t understand anything at all.

C.    They understand everything inside out.

D.    They are very intelligent.

2.      It is much more difficult to speak English than to speak French.

      A. To speak French is more difficult than to speak English.

      B. To speak English is more difficult than to speak French.

      C. Speaking English is more difficult than to speak French.

      D. Speaking French is not as difficult as to speaking English.

3.      My interview lasted longer than yours.

      A. Your interview wasn’t as short as mine.

      B. Your interview was shorter than mine.

      C. Your interview was as long as mine.

      D. Your interview was longer than mine.

4.      When I was younger, I used to go climbing more than I do now.

      A. Now I don’t go climbing anymore.

      B. I used to go climbing when I was younger.

      C. Now I don’t go climbing as much as I did.

      D. I don’t like going climbing any more.

5. Your coffee is not as good as mine.

            A. Mine is better than yours.

            B. My coffee is better than your.

            C. My coffee is better than yours.

            D. My coffee is more good than yours.

6. I can’t cook as well as my mother does.

            A. My mother can cook better than I can.

            B. My mother can’t cook better than I can.

            C. My mother can cook well than I can.

            D. I can cook better than my mother can.

7. Murder is the most serious of all crimes.

            A. Murder is very serious.

            B. No crime is more serious than murder.

            C. Everyone is very afraid of murder.

            D. Murder is the dangerous crime.

8. No one in this class as tall as peter.

            A. Peter is taller than in this class.

            B. Peter is the tallest in this class.

            C. Peter is the most tall in this class.

            D. Peter is more tall than in this class.

9. This is the best music I have ever heard.

            A. I‘ve ever heard better music than this.

            B. I‘ve ever heard such a good music as this.

            C. I‘ve ever heard so good music as this.

            D. This is the first time I‘ve heard this good music.

10. People dive fast. Many accidents happen.

A. The faster people drive, the more accidents happen.

B. The more fast people drive, the more accidents happen.

C. The much fast people drive, the more accidents happen.

D. The faster people drive, the much accidents happen.

8. I meet him much. I hate him much.

A. The better I meet him, the more I hate him.

B. The more time I meet him, the more I hate him.

C. The more I meet him, the more I hate him.

D. The better I meet him, the better I hate him

.II. Give the suitable comparion to complete each sentence. (cho dạng so sánh đúng)

1. The weather today is……hottest…. than it was yesterday. ( hot )

2. The ……largest ….. city in Canada is Toronto. ( large )

3. This story is ………funnier….. than that one. ( funny )

4. I’m taking four classes. My history class is the  ……most interesting…… of all.

( interesting )

5. The Pacific is ………deeper…. than the Mediterranean Sea. ( deep )

6. You can write …………better…… than I can ( well )

7. My father drives  ………more carefully………. than I do. ( carefully )

8. Indonesia is……larger.. than Japan in population. ( large )

9. Mt. Everest is ………the highest…… mountain in the world. ( high )

10. _______ths older___ my grandparents get, ________the happier_____ they are. (old – happy)

11. ______the hotter____ it is, ________the weaker___ Hoa is. (hot – weak)

Bài 3.

Định luật ll Niu-tơn:

\(\overrightarrow{F}+\overrightarrow{F_{ms}}=m\cdot\overrightarrow{a}\)

\(\Rightarrow F-F_{ms}=m\cdot a\)

Gia tốc vật:

\(a=\dfrac{F-F_{ms}}{m}=\dfrac{4,5-\mu mg}{m}=\dfrac{4,5-0,2\cdot1,5\cdot10}{1,5}=1\)m/s²

Vận tốc vật sau 2s:

\(v=a\cdot t=1\cdot2=2\)m/s

Bài 2: 

a: \(\Leftrightarrow4x^2-20x+25-4x^2+12x=0\)

=>-8x=-25

hay x=25/8

1. 

a) x (x - 5) + (x + 3)(x - 3)=

= x^2 - 5x + (x + 3)(x - 3)

= x^2 - 5x + x^2 - 9

= x^2 + x^2 - 5x - 9

= 2x^2 - 5x - 9.

b. không thể nhìn thấy hết bài được. Nó bị mất dấu!!

c. (20x^2 + 7x - 6) : (5x - 2)

= (5x - 2) (4x + 3) : (5x - 2)

= 4x + 3.

2. 

a. (2x - 5)^2 - 4x (x - 3)= 0

                       -8x + 25= 0

                -8x + 25 - 25= 0 - 25

                               -8x= -25

                          -8x : 8= -25 : 8

                                 x = 25/8

Vậy x= 25/8

b. 2(x - 5) - x^2 - 5x= 0

                        -10x= 0

              -10x : (-10)= 0 : (-10)

                              x= 0

Vậy x= 0

c. Lí do cũng giống câu b bài 1.

I. Choose one sentence that best rewrites the sentence given:

1.      They understand more than we do.

A.    We don’t understand as much as they do.

B.    We  don’t understand anything at all.

C.    They understand everything inside out.

D.    They are very intelligent.

2.      It is much more difficult to speak English than to speak French.

      A. To speak French is more difficult than to speak English.

      B. To speak English is more difficult than to speak French.

      C. Speaking English is more difficult than to speak French.

      D. Speaking French is not as difficult as to speaking English.

3.      My interview lasted longer than yours.

      A. Your interview wasn’t as short as mine.

      B. Your interview was shorter than mine.

      C. Your interview was as long as mine.

      D. Your interview was longer than mine.

4.      When I was younger, I used to go climbing more than I do now.

      A. Now I don’t go climbing anymore.

      B. I used to go climbing when I younger.

      C. Now I don’t go climbing as much as I did.

      D. I don’t like going climbing any more.

5. Your coffee is not as good as mine.

            A. Mine is better than yours.

            B. My coffee is better than your.

            C. My coffee is better than yours.

            D. My coffee is more good than yours.

6. I can’t cook as well as my mother does.

            A. My mother can cook better than I can.

            B. My mother can’t cook better than I can.

            C. My mother can cook well than I can.

            D. I can cook better than my mother can.

7. Murder is the most serious of all crimes.

            A. Murder is very serious.

            B. No crime is more serious than murder.

            C. Everyone is very afraid of murder.

            D. Murder is the dangerous crime.

8. No one in this class as tall as peter.

            A. Peter is taller than in this class.

            B. Peter is the tallest in this class.

            C. Peter is the most tall in this class.

            D. Peter is more tall than in this class.

9. This is the best music I have ever heard.

            A. I‘ve ever heard better music than this.

            B. I‘ve ever heard such a good music as this.

            C. I‘ve ever heard so good music as this.

            D. This is the first time I‘ve heard this good music.

10. People dive fast. Many accidents happen.

A. The faster people drive, the more accidents happen.

B. The more fast people drive, the more accidents happen.

C. The much fast people drive, the more accidents happen.

D. The faster people drive, the much accidents happen.

8. I meet him much. I hate him much.

A. The better I meet him, the more I hate him.

B. The more time I meet him, the more I hate him.

C. The more I meet him, the more I hate him.

D. The better I meet him, the better I hate him

.II. Give the suitable comparion to complete each sentence. (cho dạng so sánh đúng)

1. The weather today is……hotter…. than it was yesterday. ( hot )

2. The ……largest….. city in Canada is Toronto. ( large )

3. This story is ……funnier…….. than that one. ( funny )

4. I’m taking four classes. My history class is the  ……most interesting…… of all.

( interesting )

5. The Pacific is ………deeper…. than the Mediterranean Sea. ( deep )

6. You can write ………better……… than I can ( well )

7. My father drives  …………more carefully……. than I do. ( carefully )

8. Indonesia is…larger….. than Japan in population. ( large )

9. Mt. Everest is ………the highest…… mountain in the world. ( high )

10. ____the older______ my grandparents get, _______the happier______ they are. (old – happy)

11. _____the hotter_____ it is, _______the weaker____ Hoa is. (hot – weak)

III. Rewrite the second sentence in such a way that it has the same meaning as the one before it

1. Jane can swim further than I can

I can’t swim as far as Jane.

2. My sister can’t cook as well as my mother does

My mother can cook better than my sister.

3. I don’t play tennis as well as my brother does

My brother plays tennis better than me.

4. Apples are usually cheaper than oranges

Apples are not usually as cheap as apples.

5. Cats can’t swim as well as dogs can

Dogs can swim better than cats.

6. The dress is cheaper than the skirt

The dress is not as cheap as the dress.

7. Peter is the tallest boy in his class

No one in his class is as tall as Peter.

8. Nobody in the class is cleverer than Sally

Sally is the cleverest in the class.

9. Have you got a cheaper carpet than this?

Is this the cheapest carpet you have got?

10. They understand more than we do

We don’t understand as much as them.

11. Tom is the best football player in this team

Nobody in this team plays football as good as Tom.

12. Nothing is faster than the speed of light

The speed of light is the fastest.

13. His mother is taller than his father

His father is not as tall as his mother.

14. She’s a faster and more careless driver than I am

She drives faster and more carelessly than I do.

15. Jane is a better cook than Robert

Robert can’t cook as well as Jane.

cảm ơn bạn nhiều nhé