Cho 20 lit hỗn hợp khí methane và ethylen đi qua bình đựng dd brom 0,2 M thu được
37,6 gam dibromoethane
a. Viết PTHH?
b. Tính thể tích mỗi khí trong hỗn hợp?
c. Tính thành phần trăm theo thể tích mỗi khí trong hỗn hợp?
d. Tính thể tích dd brom cần dùng? Br = 80, C=12, H=1.

Cho 20 lit hỗn hợp khí methane và ethylen đi qua bình đựng 200 ml dd brom thu được
1,88 gam dibromoethane
a. Viết PTHH?
b. Tính thể tích mỗi khí trong hỗn hợp?
c. Tính thành phần trăm theo thể tích mỗi khí trong hỗn hợp?
d. Tính nồng độ dd brom cần dùng?

Cho 20 lit hỗn hợp khí methane và ethylen đi qua bình đựng dd brom 0,2 M thu được
37,6 gam dibromoethane
a. Viết PTHH?
b. Tính thể tích mỗi khí trong hỗn hợp?
c. Tính thành phần trăm theo thể tích mỗi khí trong hỗn hợp?
d. Tính thể tích dd brom cần dùng? Br = 80, C=12, H=1.

Cho (O;R) vẽ 2 tiếp tuyến AB , AC (A nằm (O), B , C là tiếp điểm) a) C/m tg OBAC nội tiếp đường tròn b) C/m cắt tuyến ADE (E nằm giữa A ,D). C/m: AH.AO = AE.AD c) C/m: OA vuông góc BC tại H

III. Use the correct form of the word in brackets for each gap. 1. The schoolboys were ___________ to go to the match between their school and the nearby one. (excite) 2. Many workers are ___________ to receive the pay when they start the first job.(disappoint) 3. To tell the truth, I was _________ to read the funny stories written by my classmate.(amuse) 4. All of us got ________ to hear of the accident happening to our close friend, Henry. (shock) 5. Nowadays no one is __________ to do what he wants if it does harm to the community. (freedom) 6. My pet dog is __________ to please, so I can give it anything edible. (case) 7. The _________ in the village are is sad to hear that there will be no rain in the next two weeks. (farm) 8. Green Peace is an ________ keen to protect the environment (organize) 9. The scientist is sure to find something __________ from his experiment.(use) 11. Mike failed his physics final ________ and had to sit it again. (examine) 12. Their teachers used to punish them by _________ them stay behind after school. (make) 13. Everyone agrees that a good ___________ is important. (educate) 14. This book has a very __________ introduction. (interest) 15. We find listening ________ tests rather difficult. (comprehend) 16. Ben went on to be a very __________ student at university. (success) 17. You should pay more __________ in class if you want to make progress. (attend) 18. Before you begin the exam paper, please read the instructions ________ (care) 19. In our country, children start __________ school at 12 years old.(second) 20. Ben missed the test because of his ________last Monday. (absent) 21. You must be __________ when you open that door. (care) 22. We'll live a happier and __________ life if we keep our environment clean.(health) 23. You are talking complete ___________ (sense) 25. Some __________ groups have declared a boycott of tourism on the island. (environment) 26. Air ____________ can cause illness and even death. (pollute) 27. We're very __________ about our holiday. (excite) 28. Jackson canceled the concert to the great _________ (disappoint) 29. Customers made a formal _________ treated (complain) 30. She declined his invitation because of the _________ of his fans (polite) 31. That old man told me an _________ story (amaze) 32. Gasoline fumes ________ the city air (pollution) 33. I think the careless drivers should be fined ________ (heavy) 34. Many people are concerned about the pollution of the _________ (environmental) 35. The seaside has a _________ climate (health)

IV. Fill in each blank with a correct preposition. 2. We will provide you __________ plastic bags. 3. We're afraid to say that we don't agree __________ your project. It causes many bad things ___________ the environment. 4. Tom's parents was disappointed ________ him because he failed the final test. 5. Take an umbrella ________ you. It will save you _________ getting wet on the way home 6. The boy keeps _________ asking his father _________ protecting the environment. 7. The streets are full __________ garbage 8. We are all responsible _________ keeping the environment clear and clean. 9. The park was littered _____________ bottles and cans after the festival 10. They protect these precious thing _________ being stolen. 11. The garbage bins put around the school yard is to prevent lazy students ___________ littering 12. These pollutants come __________ the land. 13. The small garden is covered __________ new grass. 14. we must do something _________ the pollution here. 15. I can get the area __________ this map.

V. Complete the sentences using because or because of: 1. It was difficult to deliver the letter ____________ the wrong address. 2. We have to cut down on our driving _____________ there is an oil shortage. 3. Rescue attempts were temporarily stopped ____________ the bad weather. 4. _______________ your advice, we didn't use that poisonous chemical. 5. Paul could not go to the football game ______________ his illness. 6. Marcella was awarded a scholarship ____________ her superior ability. 7. Nobody ventured outdoors _____________ the hurricane warnings. 8. We plan to spend our vacation in the mountains ______________ the air is purer there. 9. ____________ their good performance, they won that match. 10. The chickens have died ___________ the intense heat.

Rewrite these sentences: 1. Ms. Quyen types carefully -> Ms. Quyen __________________ 2. They are good teachers of Maths -> They __________________ 3. Juliet cycles quite slowly -> __________________ 4. Mai swam very fast -> Mai __________________ 5. Peter plays the guitar professionally -> I __________________ 6. They always think carefully -> They __________________ 7. Liz drives very carelessly -> Liz __________________ 8. He actively participated in the fight against air pollution -> He __________________

Use the correct from the words in the brackets to complete the sentences.

1. John was __________ away from home in his new job as a journalist (frequent)

2. I __________ forgot the essay about pollution and don't know what to say to the teacher (completion)

3. In the car accident, she was thrown __________ against the door (violence)

4. The company __________ agreed to move their workshop to the suburb (final)

5. Could I __________ borrow your fishing line? I need it this afternoon (possibly)

6. You must dress __________ in winter or you will catch a cold (warmth)

7. You can __________ make your enviroment better by olantung trees (ease)

8. The Green Club meets on the third sunday __________ to review what they have done (month)

9. People in China and Thailand both eat rice, but they cook it a little __________ (differ)

10. Enviromentalists work very __________ to reduce air pollution in the city (hard)

11. He was able to provide the police with some __________ information (value)

12. People say that breast-feeding is better than bottle-feeding because it's more __________ (nature)

13. He told them __________ to leave him in peace (polite)

14. I've made a __________ to the police about the noise (complain)

15. The team played very __________ (disappoint)

16. My son's teacher says that his work is often rather __________ (care)

17. Can you tell the difference between __________ mushrooms and edible varieties? (poison)

18. The __________ was turned off when I was watching TV last night (electric)

19. Smoking can cause __________ diseases (respire)

20. There were lots of kids in my __________ when I was growing up (neighbor)

21. We must learn about keeping the enviroment __________ (pollute)

22. Don't eat those vegetables. They're __________ (poison)

23. They play __________ than we do ( good)

24. To my great __________. I did not get a letter for her (disappoing)

Rewrite the sentences, using Conditional sentences 

1. Read that book, and you will understand that problem

-> If

-> Unless

2. Go to the seaside with me, and you will have a lot of fun

-> If

3. Take morning exercises regularly, and you will feel healthy

-> If

4. Nam will get better, but he has to take his medicine

-> If

5. Hoa will catch the bus, but she has to leave now

-> If

6. Ba won't be late but he has to hurry

-> If

7. Do more grammar exercises or you'll get poor marks

-> If

-> Unless

8. Hurry up or you will be late for school

-> If 

-> Unless

9. Be careful or you will fall over the rock

-> If

-> Unless