Cho 18,6g hỗn hợp X gồm Zn và Fe vào dd HCl dư. sau khi phản ứng thấy thoát ra 6,72 lít khí (đktc). phần trăm khối lượng của Zn trong hỗn hợp X?

Cho 100ml đ hỗn hợp NaF 0,1M và NaCl 0,2M vào đ AgNO3 dư. sau khi phản ứng xảy ra hoàn toàn thu được m gam kết tủa. giá trị của m là
A. 4,14
B. 2,87
C. 1,27
D. 1,6
Mọi người giải giúp mình với 

1. một gen có 3600 liên kết hidro với 900 adenin. chiều dài của gen này là?

2. một gen có 3500 liên kết hidro và hiệu số % giữa G với một nucleotit không bổ sung là 30%. số nucleotit của gen là?

3. một gen có 600A và 30% G thì số liên kết hidro của gen là?

4. một gen của vi khuẩn có chứa 16% timin thì tỉ lệ lượng G+X của gen đó là bao nhiêu %?

2 ô tô cùng xuát phát từ 2 vị trí AB cách nhau 50km chuyển động thẳng đều cùng chiều từ A đến B với vận tốc đạt được là 60 và 40 km/h

a, chọn A làm gốc tọa độ, chiều dương từ A->B. viết pt chuyển động của 2 xe

b, vẽ đồ thị chuyển động của 2 xe, cho biết 2 xe gặp nhau lúc mấy giờ, vị trí ở đâu?

c, không dùng đồ thị, xác định thời đểm và vị trí 2 xe gặp nhau

Giúp e với ạ..

Phương pháp hóa học tách ra khỏi hỗn hợp 

Giải các hệ phương trình sau:

a,

b,

c,

d,

e,

f,

g,

giúp em với ạ

Viết lại câu không đổi nghĩa:

1. We can't offer you the job because you don't know English

-> If you ..............................

2. Mr Hung was our teacher. We will never forget him 

-> Mr Hung ............................

3. This is a house. I was born and grew up in the house

-> This is a house ........................

4. You should drive carefully, or you may have an accident

-> If you don't ..........................

5. My father can speak both Vietnames and Chinese perfectly ( bilingual )

-> My father ............................

6. English has borrow many words. They come from other language

-> English has ..........................

7. My father can speak very well ( fluent )

-> My father ...........................

8. If we have more money, ................ ( viết tiếp câu điều kiện )

9. My father has decided to buy a new motorbike. His bike was stolen last week

-> My father ...................

10. Last year, I visited HCM ctiy. My uncle lives in HCM city

-> Last year ...................

11. Hoa is my friend. I will nver forget her

-> Hoa .................

12. I can't find a good job because I am not good at English

-> If I ...................

13. Hurry up, or you will miss the train

-> If you .........................

14. I am not good cooking, so I can't become a chef 

-> If .................

15. She hasn't practised her El for ages ( rusty )

-> 

16. I can speak both English and French fluently ( bilingual )

->

17. I learnt a few words of English hast summer ( picked )

->

18. I don't read many books because I don't have time 

-> If I ............

19. Mrs Nga was our teacher. We will never forget her

-> Mrs Nga................

20. This is the village. I was born and grew up in the village

-> This is....................

21. You shouldn't speak loud, or your children will wake up

-> I f you don't....................

22. I lent him a book. It was writen by Nguyen Du

-> The book......................

Mệnh đề wish:

I/ 

1. I don’t have time to go to “High Quality Good Fair “. I wish I (go)………there.

2. The weather is very hot. I wish it (be) ………………………… cooler.

3. We seldom write to her. I wish we (write) ………………… to her more often.

4. John doesn’t know how to swim. He wishes he (can) ………………..…… swim.

5. John doesn’t buy the book. She wishes she (buy) ……………………..… it.

6. Mai doesn’t pass the exam. She wishes she (study) ……………..…… harder.

7. We will not go to Ha Long Bay next week. I wish we (go) …………… there.

8. It is raining now. I wish it (stop) ……………………… raining soon.

9. My parents are not in now. I wish they (be) ……….……at home with us now.

10. I know Nam will not lend me his car . I wish he (lend). ……………… it to me.

II. Rewrite the following sentences, using "Wish"

1. I don't know more people.

I wish................................

2. I don't have a key.

I wish.................................

3. Ann isn't here.

I wish..............................

4. It is cold .

I wish..................................

5. I live in a big city (I don't like it).

I wish.................................................

6. I can't go to the party (and I like it).

I wish...............................................

7. I have to work tomorrow (I like to stay in bed).

I wish................................................

8. I don't get good marks.

I wish..............................................

9. I'm not lying on a beautiful sunny beach

I wish....................................................

10. Hoa and Ba won't go fishing this weekend.

They wish ........................................

I. Chọn đáp án đúng để hoàn thành các câu sau:

1. Make sure you ___ a hotel before you come to our island,especially in the summer

   A. keep   B. book   C. put   D. buy

2. The hotel where we are ___ is quite luxurious

   A. living   B. existing   C. staying   D. remaining

3. She speak English with a(n) ___ that I couldn't understand

   A. accent   B. stress   C. intonation   D. tone

4. He spoke a ___  of French that we found hard to understand

   A. slang   B. jargon   C. language   D. dialect

5. She ___ up some Spanish whe she was living in Mexico

   A. took   B. looked   C. picked   D. learnt

6. I can have a conversation in Italian, but I'm a ___ rusty

   A. lot   B. very   C. too   D. bit

II. Nối từ đúng với định nghĩa

Words:

1. imitate (v)

2. bilingual

3. compound

4. first language

Definitions:

A. able to speak two languages well

B. the language that you learn to speak from birth

C. copy somebody or some thing

D. a noun, an adjective, or verb made of two or more words

I/ Mark the letter A,B,C or D on your answer sheet to indicate the work whose underlined part differs from the other three in pronunciation in each of the following question

1. A. walked  B. finished  C. fixed  D. mended

2. A. spend  B. invent  C. media  D. access

II/ Mark the letter A,B,C or D on your answer sheet to indicate the work that differs from the other three in the position of primary stress in each of the following question

3. A typhoon  B disaster  C. fixed  D. experience

4. A eruption  B. tornado  C. precdict  D. snowstorm

III/ Mark the letter A,B,C or D on your answer sheet to indicate the underlined part that needs correction in each of the following question

5. It is normal for students to be nervous when they were preparing for a new school year

           A                                   B                            C        D

6. This is the best   place which   I  think of    four our holiday

                   A                    B              C                  D

7. The teacher felt angrily   when he saw   what was happening    in the classroom

                                  A                    B                           C                         D

1. It is not easy to foreign language without communicating with the native speakers

regularly.

A. master  B. challenge  C. translate  D. simplify

2. Children always want to know the reason things are as they are.

A. which  B. who  C. why  D. whom

3. Is the first of March the day the astronaut will come and give a speech at our school?

A. which  B. when  C. that  D. what

4. There are many of English all over the world such as British English, American English

and Indian English.

A. dialogues  B. varieties  C. speakers  D. terms

5. Try to the meaning of words rather than going straight for your dictionary.

A. decide  B. except  C. judge  D. guess

6. If you get when speaking, take two deep breaths before you say something.

A. pleased  B. unwilling  C. annoyed  D. nervous

7. Beet greens are the most part of the vegetable and can be cooked like any

other dark leafy green.

A. traditional  B. careful  C. colourful  D. nutritious

8. It is boring here. ever happens in this place.

A. Anything  B. Something  C. Things  D. Nothing

9. Moderation doesn’t mean the foods you love.

A. to prevent  B. preventing  C. to eliminate  D. eliminating

10. You should eat more fruits and vegetables if you to lose weight.

A. would want  B. wanted  C. will want  D. want

11.When we were on holiday, we spend too money.

A. a lot of  B. many  C. much  D. lots of

12.If people work so much, they depressed and eat more.

A. may feel  B. may have felt  C. felt  D. had felt

13.Eight o’clock is good time to phone Nick: he’s always at home in evening.

A. Ø – the  B. a – the  C. a- Ø  D. a – an

14.Does it take long time to get to city centre?

A. Ø – the  B. a – a  C. a – the  D. the – the

15.If you don’t know the language, you may have to use language.

A. hand  B. gesture  C. head  D. signal

V.Change into passivoice.

1. Mary types letters in the office.

…………………………………………………………………………………………………………

2. His father will help you tomorrow.

…………………………………………………………………………………………………………

3. Science and technology have completely changed human life.

…………………………………………………………………………………………………………

4. Peter broke this bottle.

…………………………………………………………………………………………………………

5. They are learning English in the room.

…………………………………………………………………………………………………………

6. Nothing can change my mind.

…………………………………………………

7.Has Tom finished the work?

……………………………………………

8. Did the teacher give some exercises?

……………………………………………………………

9. Have they changed the window of the laboratory?

………………………………………………………………………………

10. Is she going to write a poem?

…………………………………………………

11. Is she making big cakes for the party?

………………………………………………………………

IV. Complete the sentences with the correct form of the verbs in brackets.

1.After Nick (do)………………..his homework , he (go)………………..to bed last night.

2. Mai (live)……………..in Hai Phong for five years before she (move)…………… to Ha Noi three years ago.

3. Phong (tell)……………..me yesterday that he (learn)……………..French for a year.

4. Ms Hong (work)……………….at our school for twenty years before she (retire)………….last June.

5. By the time I (get)………………….to Nick’s house , his party (already/start)……………..

6. When we (come) ………………………..back to our home village last month , it (change)………………so much.

7. By the time the bus (come)……………this morning, Duong (wait)………………..for it for half an hour.

Help mee..

III. Complete the sentences  with the past perfect form of the verbs in brackets.

1.Anita said she was very sorry for what she (do)……………………………

2. When Sam (pay)…………………. The bill, we left the restaurant and went home.

3. It wasn’t surprising that she was tired .She (not sleep)………………….. for two days.

4. The road was blocked because a lorry (break down)………………………..

5. My mother felt very nervous on the plane because she (not fly)………………..before.

6……………………………….(they/go) home when you arrived?

7. I (hear)……………the story before , so I didn’t find it very interesting.

8. After she (try on)…………………….. all the dresses in the shop, she bought the most expensive one.

9. They (not have)………………..breakfast when I got up.

10. The children were very  excited because they (not see)………………….a tiger before.

Giup mình, mình cần gấp..

Dẫn 11,2 lít hh A gồm CH4, C2H4, CO2 lần lượt qua bình (1) chứa dd Ca(OH)2 dư và bình (2) chứa dd brom dư. Thấy bình (1) xuất hiện 10 gam kết tủa, bình 2 khối lượng tăng thêm 2,8 gam.

a.Viết các pt

b.Tính % V mỗi khí trong hh A

(Biết NTK:  H =1; O =16; C = 12; Br = 80, Ca = 40)

Có 2 lọ hóa chất mất nhãn đựng 2 khí không màu là metan và etilen. Trình bày phương pháp hóa học nhận ra mỗi chất trong từng lọ hóa  chất trên

a, Viết các công thức cấu tạo dạng mạch thẳng, nhánh(nếu có) của các  phân tử sau: C3H8, CH3Br, C2H6O

b, Viết các công thức cấu tạo dạng mạch vòng của các  phân tử sau:  C4H8 , C3H6       

Đốt cháy hoàn toàn 4,48 lít (đktc) hợp chất hữu cơ A thu được 8,96 lít khí CO, (đktc) và 3,6 gam nước. Biết ở đktc 0,5 lít khí A có khối lượng là 0,58 gam. Hãy xác định công thức phân tử của A, viết công thức cấu tạo. Cho C= 12, O= 16, H=1

HELP MEE!!

Cho 3,36 lít (đktc) hỗn hợp khí gồm metan và etilen tác dụng hết với dung dịch brom dư thì thấy khối lượng brom tham gia phân ứng là 8 gam. al Tính thành phần % về thể tích của mỗi khí trong hỗn hợp. b/ Tính thể tích khí oxi (đktc) cần để đốt cháy hết hỗn hợp khí trên. (cho C = 12, H =1, Br = 80, O = 16) 

GIÚP MÌNH!!