Oxi hoá butane bằng oxygen ở 180^oC và 70 bar tạo thành sản phẩm hữu cơ X duy nhất. X là
A. HCOOH.

B. CH₃COOH.

C. C₂H₅COOH.

D. CO₂.

- Assistant: “Is there anything I can do for you, sir?”

           - Customer: “________”

Cho các chất sau: (1) 2-methylbutane; (2) 2-methylpentane; (3) 3-methylpentane; (4) 2,2-dimethylbutane và (5) benzene.

Trong số các chất này, có bao nhiêu chất có thể là sản phẩm reforming hexane?
A. 5.
B. 2.
C. 3.
D. 4.

Trộn neopentane với chlorine và chiếu ánh sáng tử ngoại thì thu được tối đa bao nhiêu sản phẩm monochlorine?
A. 1.
B. 2.
C. 3.
D. 4.

“I wouldn’t do that if I were you.” – “________”

Tính các giới hạn sau:

a) $\underset{n\to +\infty }{\lim }\left(\sqrt{n^2+2n}-n-2\right)$ ;

Cho các alkane kèm theo nhiệt độ nóng chảy và nhiệt độ sôi ^oC sau: propane (-187,7 và - 42,1), butane (-183,3 và -0,5), pentane (-129,7 và 36,1), hexane (- 95,3 và 68,7).

Số alkane tồn tại ở thể khí ở điều kiện thường là
A. 1.
B. 2.
C. 3.
D. 4.

“ Have a nice day.” – “________”.

Tên gọi của alkane nào sau đây đúng?
A. 2-ethylbutane.
B. 2,2-dimethylbutane.
C. 3-methylbutane.
D. 2,3,3-trimethylbutane.

Alkane (CH₃)₃C-CH₂-CH(CH₃)₂ có tên gọi là
A. 2,2,4-trimethylpentane.
B. 2,4,4-trimethylpentane.
C. pentamethylpropane.
D. trimetylpentane.

“Do you agree that our natural resources will soon end?” – “________”.

“Sugar?”

“What’s date is your wedding anniversary, Rose?” – “It’s________.”

"________." - "Never mind, better luck next time."

– “What do you usually do at weekend?” – “_______.”

– “Thanks for the lovely party.” – “_______.”

– “ Has an announcement been made about the eight o’clock flight to Paris?”

-“_____________.”

– “ Would you mind lending me your bike?”

                       - “___________________________.”

Tính các giới hạn sau:

b) $\underset{n\to +\infty }{\lim }\frac{2^n+3}{1+3^n}$ .

Do you have a minute, Dr Keith?” -“_______________________”

Tính các giới hạn sau:

a)  $\underset{n\to +\infty }{\lim }\frac{n^2+1}{2n^2+n+2}$;

“ Would you like another coffee?” -“___________________________”

“ If only I hadn’t lent him all my money!” –“____________________”

– “ Sorry, I’m late”                    - “______________________”

“Would you like me to get a cab?”

                       “________"

“Mum! I’ve got 7 on the IELTS test.”

                       “________”

- Don’t forget to do as I have told you.

-____________.

- I can’t see the view very well from here.

-____________.

John was in Hanoi and wanted to send a parcel to his parents. He asked a local passer-by the way to the post-office. Choose the most suitable response to fill in the blank in the following exchange.

John: “Can you show me the way to the nearest post office, please?”

Passer-by: “________”

Bob: “Thank you very much for a lovely party” – Bill: “______!”

James: “What’s the matter?” - Anne: “________”

“What a great haircut, Lucy!” - “________”

A: I had a really good weekend at my uncle’s.

                       B: “________”.

Adam: "It was very kind of you to help me out, Anna?"

Anna: “________”

Tom:" Would you take this along to the office for me?"

Jerry:" ________"

Peter: “I’ve been awarded a scholarship to study in America.”

Kate: “Uh, really? ________!”