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8 tháng 2 2022

STT 

Thí nghiệm 

Hiện tượng-PTHH 

Nhúng quì tím vào dd axit axetic  

 

 Quỳ tím hoá đỏ

Cho mẩu magie vào dung dịch axit axetic

 

 - Hiện tượng: Mẩu Magie tan trong dung dịch axit axetic, tạo thành dung dịch, có khí không màu thoát ra sau phản ứng

\(PTHH:Mg+2CH_3COOH\rightarrow\left(CH_3COO\right)_2Mg+H_2\uparrow\)

Nhỏ dd NaOH vào ống nghiệm, thêm phenolphthalein, nhỏ dd axit axetic vào dd. 

 

 - Hiện tượng: Sau khi nhỏ thêm phenolphtalein thì dung dịch chuyển sang màu hồng. Sau khi thêm dung dịch axit axetic vào thì dung dịch mất màu hồng.

\(PTHH:NaOH+CH_3COOH\rightarrow CH_3COONa+H_2O\)

Nhỏ dd NaOH vào ống nghiệm, thêm phenolphthalein, nhỏ dd axit axetic vào dd. 

 

 Này giống thì nghiệm 3 em nè

Nhỏ dung dịch axit axetic vào CuO 

 

 

 - Hiện tượng: CuO tan trong dung dịch axit axetic tạo thành dung dịch.

\(PTHH:CuO+2CH_3COOH\rightarrow\left(CH_3COO\right)_2Cu+H_2O\)

Nhỏ từ từ dung dịch axit axetic vào Na2CO3 

 

 

 - Hiện tượng: Sau phản ứng thấy có sủi bọt khí.

\(PTHH:Na_2CO_3+2CH_3COOH\rightarrow2CH_3COONa+CO_2\uparrow+H_2O\)

Ông này lớp mấy dzậy ??

11 tháng 4 2017

Tính chất của nhôm

ứng dụng của nhôm

1

Dẫn điện t ốt

làm dây dẫn điện

2

Nhẹ, bền

Chế tạo máy bay, ô tô, xe lửa ,….

3

nhôm dẻo nên có thể cán thành đồ dùng bằng nhôm

làm dụng cụ gia đình: nồi xoong, khung cửa…..



12 tháng 4 2017

Giải

Có liên kết đôi Làm mất màu dd Brom Phản ứng trùng hợp Tác dụng với oxi
Metan không không không
Etilen có 1 liên kết đôi

13 tháng 4 2017
Có liên kết đôi Làm mất màu dd Brom Phản ứng trùng hợp Tác dụng với oxi
Metan không không không
Etilen có 1 liên kết đôi
6 tháng 1 2019

Giải thích

1 Axit làm quỳ tím chuyển thành màu đỏ

2 Axit + Kim Loại \(\rightarrow\) Muối + \(H_2\)

3 Axit + Bazơ \(\rightarrow\) Muối + \(H_2O\)

28 tháng 4 2017

a) Phản ứng giữa các dung dịch trên đều thuộc loại phản ứng trao đổi, muốn xảy ra được sản phẩm phải có chất không tan, chất khí hoặc H2O.

Hỏi đáp Hóa học

9 tháng 4 2019

+Rượu etylic: tác dụng với Na (tạo ra khí H2 thường dùng để nhận biết)

C2H5OH + Na => C2H5ONa + 1/2 H2

+Axit axetic: Tác dụng với NaHCO3

CH3COOH + NaHCO3 => CH3COONa + CO2 + H2O

+Glucozo:

-Phản ứng tráng gương (phản ứng đặc trưng, dùng để nhận biết --> tạo kết tủa trắng bạc)

C6H12O6 + Ag2O => (NH3) C6H12O7 + 2Ag|

-Lên men tạo thành rượu và khí cacbonic

C6H12O6 => (men rượu, to) 2C2H5OH + 2CO2

axit là hợp chất mà trong đó có một hay nhiều nguyên tử hidro liên kết với một gốc axit

12 tháng 12 2018
TT CTHH của axit Số nguyên tử H trong phân tử axit Gốc axit
2 HNO2 1 -NO2
3 H2SO4 2 =SO4
4 H2CO3 2 =CO3

- Theo em axit là những hợp chất mà phân tử gồm có một hay nhiều nguyên tử hiđrô liên kết với gốc axit

28 tháng 4 2017

Phương trình hóa học của các phản ứng:

Pb(NO3)2 + Na2CO3 2NaNO3 + PbCO3

Pb(NO3)2 + 2KCl → 2KNO3 + PbCl2

Pb(NO3)2 + Na2SO4 → 2NaNO3 + PbSO4

BaCl2 + NaCO3 → 2NaCl + BaCO3

BaCl2 + Na2SO4 → 2NaCl + BaSO4


14 tháng 10 2020
Na2CO3 KCl Na2SO4 NaNO3
Pb(NO3)2 x x x o
BaCl2 x o x o

Phương trình hóa học của các phản ứng:

Pb(NO3)2 + Na2CO3 → PbCO3 ↓ + 2NaNO3

Pb(NO3)2 + 2KCl → PbCl2 ↓ + 2KNO3

Pb(NO3)2 + Na2SO4 → PbSO4 ↓ + 2NaNO3

BaCl2 + Na2CO3 → BaCO3 ↓ + 2NaCl

BaCl2 + Na2SO4 → BaSO4 ↓ + 2NaCl.

Choose the best option to complete each of the following sentences.  5. You can speak English fluently, __________?A. could youB. can’t you C. can you D. couldn’t you   6. On average, _________Moon is 384.400 km from ___________ Earth.A. the-theB. x-theC. a-an D. a-the  7. _________ my opinion, he is the best football player in our team.A. OnB. AtC. InD. From  8. On March 8th , women often _____ beautiful roses, postcards, lots of gifts with the best   wishes from their relatives and...
Đọc tiếp

Choose the best option to complete each of the following sentences.

  5. You can speak English fluently, __________?

A. could you

B. can’t you

C. can you

D. couldn’t you

  6. On average, _________Moon is 384.400 km from ___________ Earth.

A. the-the

B. x-the

C. a-an

D. a-the

  7. _________ my opinion, he is the best football player in our team.

A. On

B. At

C. In

D. From

  8. On March 8th , women often _____ beautiful roses, postcards, lots of gifts with the best   wishes from their relatives and friends.

A. give

B. send

C. have

D. receive

  9. The driver stopped ______ a coffee because he felt sleepy.

A. have

B. to have

C. having

D. had

  10. I wish I ______ play football well.

A. can

B. could

C. am

D. did

  11. If I ________ you, I would join this English Speaking Contest.

A. were

B. am

C. would be

D. will be

  12. _______ there is a lot of noise in the city, I like living there.

A. Because

B. Despite

C. In spite of

D. Although

  13. I suggest ________ a shotcut through the field . It will take much less time.

A. take

B. taking

C. to take

D. takes

  14. She has a lot of ___________ while she’s studying English.

A. difficult

B. difficulties

C. difficile

D. diffident

   15. He finds the way to a place easily. He was a very good sense of ___________

A. direction

B. humor

C. style

D. responsibility

16. There are lots of people who _____ work in remote and mountainous areas  nowadays.

A. volunteers

B. voluntary

C. voluntarily

D. volunteer

   17. If you want to _____ the other students in your class, you’ll have to work very hard.

A. catch up with

B. learn on

C. catch up

D. hurry up

 

  Mark the letter A, B,C or D to indicate the correct answer to each of the following        questions.

  18. -  Mary: “ Thank s for your help, John.”    

        - John:   “ ______________”

A. There’s nothing

C. It’s my pleasure

B. Nothing

D. It sounds good

   19. – Lan: “ Do you think Covid-19 is one of the most dangerous diseases?”

         -  Mai: “ ________________”

A. Well that’s very surprising

C. Not at all. Go ahead.

B. Sure. Thanks.

D. There’s no doubt about it.

   

  Choose one underlined part that is incorrect in each of the sentences.

   20. Some of the students seemed very nervously before the final exam.

             A                         B                                    C          D

   21. The number of students are not large, therefore, a number of tickets are available to   

               A                                      B                                                   C                                          D

   them.   

    22. You should take the raincoat with you in case it will rain hard this afternoon.

                                A                         B               C              D

    23. Her sister always runs more quickly as her.

                                A       B               C       D                   

    24. As soon as he completes his homework, he helps feed the chickens and collects the

                                     A                         B                                              C                 D

     eggs.

    Choose the sentence that is closest in meaning to each of the sentences given.

    25. My father often played football when he was young.

    A. My father used to play football when he is young.

    B. My father used to play football when he was young.

    C. My father used to playing football when he was young.

    D. My father used to playing football when he be young.

    26. The teacher said “ You must prepare your lessons before going to class”.

    A. The teacher said that you must prepare your lessons before going to class.

    B. The teacher said that we must prepare your lessons before going to class.

    C. The teacher said that we had to prepare our lessons before going to class.

    D. The teacher said that we had to  preparing our lessons before going to class.

    27. He bought this book last week.

    A. This book was bought by him last week.

    B. Last week, this book was bought by him.

    C. This book is bought by him last week.

    D. This book was bought by he last week.

    Choose the sentence that best combines each given pair of sentences.

    28. I was very tired. I went to bed early.

    A. I was very tired but I went to bed early.

    B. Although I was very tired but I went to bed early.

    C. I went to bed early when I was very tired

    D. I went to bed early because I was very tired.

   29. He was sitting on a chair. It was uncomfortable.

    A. The chair who he was sitting on was uncomfortable.

    B. The chair which he was sit on was uncomfortable.

    C. The chair which he was sitting on was uncomfortable.

    D. The chair whom he was sitting on was uncomfortable.

30. They heard about his bad marks. They were sad.

   A. They are sad that they heard about his bad marks.

   B. They were sad because of they heard about his bad marks.

   C. They were sad that they heard about his bad marks.

   D. They were sad so they heard about his bad marks.

   Read the following passage and choose the correct answer.

       I began teaching career nearly six years ago. I spent six years (31) _____ in a remote      village where the villagers were very poor and the living standard was low. Sometimes I was very (32)______ because of bad living condition (33)________ low pay. I was really homesick. However, at that time, with my youth enthusiasm. I tried my best to devote myself to the noblest career that was ‘teaching’. I love my poor (34)________ students (35)_______ were living in poverty. Despite the poor life, they couldn’t suffer from empty mind.

31. A. taught

B.  teaching

C. teaches

D. to teach

32.A disappointed

B. disappoints

C. disappointing

D. disappoint

33. A. so

B. because

C. and

D. although

34. A. few

B. less

C. some

D. little

35. A. who

B. which

C. whom

D. where

Read the passage and choose the best answer for each question.

Truong Yen Festival is from the 9th to the 11th day of the third lunar month, the main festival day is on the 10th day of the third lunar month. This festival is celebrated in Truong Yen Commune, Hoa Lu District, Ninh Binh Province and by the locals. The festival is in memory of the Kings of the Dinh and Le dynasties. The festival lasts for three days with many traditional games and martial arts. There are many cultural and sports activities, including a procession to carry water from the Hoang Long River to the King Dinh and King Le temples, a drum festival, and volleyball, human chess, and folk games... The most special about the Truong Yen Festival is a game called " maneuver game with red flag", which replays the childhood of Dinh Bo Linh as a buffalo boy in Truong Yên.

 36. What is the best title of the passage?

A. The Kings Festival

C. Activities of a Festival   

B. The Festival in Ninh Binh Province

D. Truong Yen Commune

 37. How long does Truong Yen Festival last?

A. Three days        

C. On the 10th day 

B. From the 9th to the 11th day.

D. During the third lunar month.

38. What is the most special about the Truong Yen Festival?

A. Many traditional games and martial arts.

B. Many cultural and sports activities.

C.  The game replays the childhood of the King Dinh.

D.  In memory of the Kings of the Dinh and Le dynasties.

39. What does the word “which” in the passage mean?

A. Martial arts         B. Cultural activities           C. Sports activities        D. A game

40. Which of the following is not TRUE?

A. The festival is in honor of the Kings of the Dinh and Le dynasties.

B. The third day of the tenth lunar month is the main festival day.

C. There are many traditional games and martial arts.

       D. Dinh Bo Linh was a buffalo boy in Truong  Yen      

2
4 tháng 3 2022

Có gì đó sai sai thì phải, Anh -> Hoá:)

4 tháng 3 2022

  5. You can speak English fluently, __________?

A. could you

B. can’t you

C. can you

D. couldn’t you

  6. On average, _________Moon is 384.400 km from ___________ Earth.

A. the-the

B. x-the

C. a-an

D. a-the

  7. _________ my opinion, he is the best football player in our team.

A. On

B. At

C. In

D. From

  8. On March 8th , women often _____ beautiful roses, postcards, lots of gifts with the best   wishes from their relatives and friends.

A. give

B. send

C. have

D. receive

  9. The driver stopped ______ a coffee because he felt sleepy.

A. have

B. to have

C. having

D. had

  10. I wish I ______ play football well.

A. can

B. could

C. am

D. did

  11. If I ________ you, I would join this English Speaking Contest.

A. were

B. am

C. would be

D. will be

  12. _______ there is a lot of noise in the city, I living there.

A. Because

B. Despite

C. In spite of

D. Although

  13. I suggest ________ a shotcut through the field . It will take much less time.

A. take

B. taking

C. to take

D. takes

  14. She has a lot of ___________ while she’s studying English.

A. difficult

B. difficulties

C. difficile

D. diffident

   15. He finds the way to a place easily. He was a very good sense of ___________

A. direction

B. humor

C. style

D. responsibility

16. There are lots of people who _____ work in remote and mountainous areas  nowadays.

A. volunteers

B. voluntary

C. voluntarily

D. volunteer

   17. If you want to _____ the other students in your class, you’ll have to work very hard.

A. catch up with

B. learn on

C. catch up

D. hurry up

 

22 tháng 9 2019

So sánh các điều kiện: nồng độ axit, nhiệt độ của dung dịch H2SO4 loãng và trạng thái của sắt với thời gian phản ứng để rút ra:

a) Thí nghiệm 2,thí nghiệm 4, thí nghiệm 5 chứng tỏ phản ứng xảy ra nhanh hơn khi tăng nhiệt độ của dung dịch H2SO4 .

b) Thí nghiệm 3 và thí nghiệm 5 chứng tỏ phản ứng xảy ra nhanh hơn khi tăng diện tích tiếp xúc.

c) Thí nghiệm 4 và thí nghiệm 6 chứng tỏ phản ứng xảy ra nhanh hơn khi tăng nồng độ của dung dịch H2SO4.

23 tháng 9 2019

a) Phản ứng xảy ra nhanh hơn khi tăng nhiệt độ: 2,4,5

b) Phản ứng xảy ra nhanh hơn khi tăng diện tích tiếp xúc: 3,5

c) Phản ứng xảy ra nhanh hơn khi tăng nồng độ axit: 4,6