este metyl propionat có công thức cấu tạo là:

Để phản ứng hết với một lượng hỗn hợp gồm hai chất hữu cơ đơn chức X và Y (M_X < M_Y) cần vừa đủ 300 (ml) dung dịch NaOH 1M. Sau khi phản ứng xảy ra hoàn toàn thu được 24,6 gam muối của một axit hữu cơ và m gam một ancol. Đốt cháy hoàn toàn lượng ancol trên thu được 4,48 lít CO₂ (đktc) và 5,4 gam H₂O. Công thức của Y là:

Dùng những hóa chất nào để nhận biết: axit axetic, axit acrylic, anđehit axetic, metyl axetat?

Đun nóng 0,1 mol chất A với một lượng vừa đủ dd NaOH thu được 13,4 g muối của 1 axit hữu cơ và 9,2 g một ancol đơn chức. Cho ancol đó bay hơi ở 127°C và 600 mm Hg thì chiếm thể tích là 8,32 lít. Công thức nào sau đây của A là phù hợp?

Lần lượt cho các chất vinyl axetat, 2,2-điclopropan; phenyl axetat và 1,1,1-tricloetan tác dụng hoàn toàn với dung dịch NaOH dư. Trường hợp nào sau đây phương trình hóa học không viết đúng:

Oxi hóa một ancol đơn chức no A có bột Cu xúc tác, được B. Oxi hóa B với xúc tác Pt thu được axit D. Cho D tác dụng với dung dịch kiềm được muối E. Cho E tác dụng với dung dịch AgNO₃ trong NH₃ được Ag kim loại.Công thức cấu tạo của A, B, D, E lần lượt là:

Số đồng phân của hợp chất hữu cơ có công thức phân tử C₅H₁₀O₂ có thể tác dụng với dung dịch NaOH nhưng không tác dụng với kim loại Na là:

Lần lượt cho các chất vinyl axetat; 2,2-điclopropan; phenyl axetat và 1,1,1-tricloetan tác dụng hoàn toàn với dung dịch NaOH dư. Trường hợp nào dưới đây phản ứng đã không được viết đúng?

Đốt cháy hoàn toàn 7,4 g hỗn hợp 2 este đồng phân thu được 6,72 lít CO₂ (đktc) và 5,4 g H₂O. CTCT 2 este là:

Số đồng phân este ứng với công thức phân tử C3H6O2 là

X là este tạo được giữa glixeiol và hai axit (fomic và axetic). X tác dụng được với Na giải phóng H₂. Tổng số công thức cấu tạo thỏa mãn điều kiện của X là:

Đốt cháy hoàn toàn 0,11 gam một este X (tạo nên từ một axit cacboxylic đơn chức và một ancol đơn chức) thu được 0,22 gam CO₂ và 0,09 gam H₂O. Số este đồng phân của X là:

Cho 45 (gam) trieste của glixerol với một axit béo tác dụng vừa đủ với 100 (ml) dung dịch NaOH 1,5M được m₁ (gam) xà phòng và m₂ (gam) glixerol. Giá trị của m₁ và m₂ lần lượt là:

este metyl propionat có công thức cấu tạo là:

Câu nào sau đây không đúng?

Chất hữu cơ X có CTPT là C₈H₈O₂. Đun nóng X trong NaOH thu được 2 muối. Số đồng phân cấu tạo của X là:

Hỗn hợp X gồm hai este no, đơn chức, mạch hở. Đốt cháy hoàn toànmột lượng X cần dùng vừa đủ 3,976 lít khí O₂ (ở đktc), thu được 6,38 gam CO₂. Mặt khác, X tác dụng với dung dịch NaOH, thu được một muối và hai ancol là đồng đẳng kế tiếp. Công thức phân tử của hai este trong X là:

Este đơn chức X có tỉ khối hơi so với CH₄ là 6,25. Cho 20 gam X tác dụng với 300 (ml) dung dịch KOH 1M (đun nóng). Cô cạn dung dịch sau phản ứng thu được 28 gam chất rắn khan. Công thức cấu tạo của X là:

Xà phòng hóa hoàn toàn 0,1 mol một chất hữu cơ X (chứa C, H, O) cần vừa đủ 300 ml dung dịch NaOH 1M cô cạn dung dịch sau phản ứng thu được 24,6 gam muối khan. CTPT của X là:

Đun nóng 0,05 (mol) X với lượng vừa đủ dung dịch NaOH thu được 6,7 (gam) muối của axit hữu cơ đa chức Y và 4,6 (gam) ancol đơn chức Z. Cho ancol Z bay hơi ở 127°C và 300 (mmHg) sẽ chiếm thể tích là 8,32 (lít). Công thức của X là:

X là hỗn hợp 2 este của cùng 1 ancol no, đơn chức và hai axit no, đơn chức đồng đẳng kế tiếp. Đốt cháy hoàn toàn 0,1 mol X cần 6,16 lít O₂ (đktc). Đun nóng 0,1 mol X với 50 gam dung dịch NaOH 20% đến phản ứng hoàn toàn, rồi cô cạn dung dịch sau phản ứng được m gam chất rắn. Giá trị của m là:

Read the following passage and mark the letter A,B ,C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Organized football games began in 1863. In football, two (31)_____ of eleven players try to kick or head the ball into the goal of the other team. The goal keeper, (32)_____tries to keep the ball out of the goal, is the only player on the field who can touch the ball with his or her hands. The other players must use their feet, heads and bodies to (33)_____ the ball. Every four years, football teams around the world (34)_____ for the World Cup. The World Cup competition started in 1930. Brazil is the home of many great football players, including the most famous player of all, Pele’. With his fast dazzling speed, Pele’ played for many years in Brazil and then in New York. People in more than 140 countries (35)_____ the world play football. It is definitely the world’s most popular sport.  

Question 32:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Engineers have been dreaming of an underwater link between Britian and France since 1802. Finally, in 1994 the Channel Tunnel ( nickname ”the Chunnel” by the English) was officially opened. This fifteen million dollar project took seven years to complete. It is 50km long and built 45 metres under the seabed. The trains which go through the Chunnel can travel at up to 300km/h due to the(31)…… electrical system. The journey from London to Paris via the Chunnel takes just three hours. It is also handy for drivers since they can load their cars onto the trains. They don't need to book in(32)……… as trains depart every few minutes. However, while on the train, there isn't much to do and many criticise the Chunnel for this. Unlike the ferries, there is no duty-free shopping, no video game parlour or refreshment stand(33).……… can you look outside and enjoy the view. As a result, many would find the Chunnel(34)……and would take the ferry(35)……  

Question 31:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Engineers have been dreaming of an underwater link between Britian and France since 1802. Finally, in 1994 the Channel Tunnel ( nickname ”the Chunnel” by the English) was officially opened. This fifteen million dollar project took seven years to complete. It is 50km long and built 45 metres under the seabed. The trains which go through the Chunnel can travel at up to 300km/h due to the(31)…… electrical system. The journey from London to Paris via the Chunnel takes just three hours. It is also handy for drivers since they can load their cars onto the trains. They don't need to book in(32)……… as trains depart every few minutes. However, while on the train, there isn't much to do and many criticise the Chunnel for this. Unlike the ferries, there is no duty-free shopping, no video game parlour or refreshment stand(33).……… can you look outside and enjoy the view. As a result, many would find the Chunnel(34)……and would take the ferry(35)……  

Question 33:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:

Engineers have been dreaming of an underwater link between Britian and France since 1802. Finally, in 1994 the Channel Tunnel ( nickname ”the Chunnel” by the English) was officially opened. This fifteen million dollar project took seven years to complete. It is 50km long and built 45 metres under the seabed. The trains which go through the Chunnel can travel at up to 300km/h due to the(31)…… electrical system. The journey from London to Paris via the Chunnel takes just three hours. It is also handy for drivers since they can load their cars onto the trains. They don't need to book in(32)……… as trains depart every few minutes. However, while on the train, there isn't much to do and many criticise the Chunnel for this. Unlike the ferries, there is no duty-free shopping, no video game parlour or refreshment stand(33).……… can you look outside and enjoy the view. As a result, many would find the Chunnel(34)……and would take the ferry(35)……  

Question 32:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

My home is in the air – I do an enormous amount of travelling. It is a fast life and full of work, but I like it and that is the only way (31)..................me. Everything is tiring – music, travelling – but what can I do? I am not (32).................to complaining. It is hart to imagine now that I will never be very long in one place. My home town is on the Caspian Sea. There is sea, wind, sun and too many tourists and hotels. I have my own flat with four or five rooms. But I am seldom there. If I am there for a day or two I prefer to (33)................ with my mother and grandmother. They live in a small house, but it is very comfortable and my mother cooks for me. I like good, simple food. I have no wife, no brothers or sisters and my father died when I was seven. He was an engineer and I don’t ( 34).............him very well. He liked music very much and wanted me to (35)..............a musician.  

Question 31:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

My home is in the air – I do an enormous amount of travelling. It is a fast life and full of work, but I like it and that is the only way (31)..................me. Everything is tiring – music, travelling – but what can I do? I am not (32).................to complaining. It is hart to imagine now that I will never be very long in one place. My home town is on the Caspian Sea. There is sea, wind, sun and too many tourists and hotels. I have my own flat with four or five rooms. But I am seldom there. If I am there for a day or two I prefer to (33)................ with my mother and grandmother. They live in a small house, but it is very comfortable and my mother cooks for me. I like good, simple food. I have no wife, no brothers or sisters and my father died when I was seven. He was an engineer and I don’t ( 34).............him very well. He liked music very much and wanted me to (35)..............a musician.  

Question 32:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35:

Education is more important today than ever before. It gives them the specialized training they may need to (31)_______ for a job or career. For example, a person must meet certain educational requirements and obtain a license or certificate before he can practice law or medicine. Many fields, like computer operation or police work, (32)_______ satisfactory completion of special training courses. Education is also important (33)_______ it helps people get more out of life. It increases their knowledge and understanding of the world. It helps them acquire the skills that make life more interesting and enjoyable, such as the skills needed to participate in a sport, paint a picture, or play a musical instrument. Such education becomes (34)_______ important as people gain more and more leisure time. Education also helps people adjust to change. This habit has become necessary because social changes today take place with increasing speed and affect the lives of more and more people. Education can help a person understand these changes and provide him (35)____the skills for adjusting to them.

Question 33:

Question 32: 

HOW TO AVOID MISCOMMUNICATION IN THE WORKPLACE

As a small-business owner, you can avoid many problems simply by improving communication in your office. By clarifying everyone's expectations and roles, you'll help to (30) _______greater trust and increased productivity among employees. Here are a few tips for doing so. Practice active listening. The art of active listening includes (31)_______ close attention to what another person is saying, then paraphrasing what you've heard and repeating it back. Concentrate (32)_______ the conversation at hand and avoid unwanted interruptions (cell phone calls, others walking into your office, etc.). Take note of how your own experience and values may color your perception. Pay attention to non-verbal cues. We don't communicate with words alone. Every conversation comes with a host of non-verbal cues-facial expressions, body language, etc. - that may (33)_______ contradict what we're saying. Before addressing a staff member or (34)_______ a project conference, think carefully about your tone of voice, how you make eye contact, and what your body is "saying". Be consistent throughout. Be clear and to the point. Don't cloud instructions or requests with irrelevant details, such as problems with past projects or issues with long-departed personnel. State what you need and what you expect. Ask, "Does anyone have any questions?" Demonstrate that you prefer questions up-front as opposed to misinterpretation later on. 

Question 33:

HOW TO AVOID MISCOMMUNICATION IN THE WORKPLACE

As a small-business owner, you can avoid many problems simply by improving communication in your office. By clarifying everyone's expectations and roles, you'll help to (30) _______greater trust and increased productivity among employees. Here are a few tips for doing so. Practice active listening. The art of active listening includes (31)_______ close attention to what another person is saying, then paraphrasing what you've heard and repeating it back. Concentrate (32)_______ the conversation at hand and avoid unwanted interruptions (cell phone calls, others walking into your office, etc.). Take note of how your own experience and values may color your perception. Pay attention to non-verbal cues. We don't communicate with words alone. Every conversation comes with a host of non-verbal cues-facial expressions, body language, etc. - that may (33)_______ contradict what we're saying. Before addressing a staff member or (34)_______ a project conference, think carefully about your tone of voice, how you make eye contact, and what your body is "saying". Be consistent throughout. Be clear and to the point. Don't cloud instructions or requests with irrelevant details, such as problems with past projects or issues with long-departed personnel. State what you need and what you expect. Ask, "Does anyone have any questions?" Demonstrate that you prefer questions up-front as opposed to misinterpretation later on. 

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks:   

There are several changes in the procedure for employees ___5___ wish to apply for vacant positions within the company. These changes make it much easier for in-house employees to fill vacancies that occur. First, __6__ most important difference is that employees will now be notified of all available positions before the positions are advertised for the general public. Accordingly, all in-house candidates will be interviewed before we see any out-side candidates, and we will offer the job to outside candidates only if no current employees are able to fill the position. Second, under the new procedure, in-house employees can be hired even if they don’t __7__ all job requirements. Under our old policy, in-house employees had to meet all job qualifications in order to obtain the vacant position. Now, however, employees who have proven themselves dedicated __8__ the company will be hired for a vacant position even if they are lacking some minor qualifications; training will be provided. A third change involves recommendations. Form now on, employees do not need to be recommended for an in-house position before they __9__. Instead, employees may apply as soon as they are aware of the vacancy. The remaining procedures and policies (those regarding increase in pay, interview procedure, and hiring approval) remain the same.

Question 7: