Este X có chứa vòng benzen và có công thức phân tử là C₈H₈O₂. Số đồng phân cấu tạo của X là:

Hỗn hợp X gồm 2 chất hữu cơ A, B chỉ chứa một loại nhóm chức. Cho m gam X tác dụng hết với NaOH thu được một muối của axit hữu cơ đơn chức và hỗn hợp 2 ancol, tách nước hoàn toàn hai ancol này ở điều kiện thích hợp chỉ thu được một anken làm mất màu 24 gam Br₂. Biết A, B chứa không quá 4 nguyên tử C trong phân tử. Giá trị của m là:

Este X có chứa vòng benzen và có công thức phân tử là C₈H₈O₂. Số đồng phân cấu tạo của X là:

Một loại chất béo chứa 88,4% triolein, còn lại là tạp chất trơ. Chỉ số este của chất béo trên là:

Trong một bình kín chứa một este no, đơn chức, mạch hở X và O₂ (số mol O₂ gấp đôi số mol cần cho phản ứng cháy) ở 139,9°C, áp suất trong bình là 0,8 atm. Đốt cháy hoàn toàn X sau đó đưa về nhiệt độ ban đầu, áp suất trong bình lúc này là 0,95 atm. Công thức phân tử của X là:

Hợp chất hữu cơ X tác dụng được với dung dịch NaOH đun nóng và với dung dịch AgNO₃ trong NH₃. Thể tích của 3,7 gam hơi chất X bằng thể tích của 1,6 gam khí O₂ (cùng điều kiện về nhiệt độ và áp suất). Khi đốt cháy hoàn toàn 1,0 gam X thì thể tích khí CO₂ thu được vượt quá 0,7 lít (ở đktc). Công thức cấu tạo của X là:

Xà phòng hóa hoàn toàn 14,55 gam hỗn hợp hai este đơn chức X, Y cần 150 ml dung dịch NaOH 1,5 M. Sau phản ứng cô cạn dung dịch thu được hỗn hợp hai ancol đồng đẳng kế tiếp và một muối duy nhất. Công thức cấu tạo thu gọn của hai este là:

Hỗn hợp X gồm axit HCOOH và axit CH₃COOH (tỉ lệ mol 1 : 1). Hỗn hợp Y gồm ancol CH₃OH và ancol C₂H₅OH (tỉ lệ mol 3 : 2). Lấy 11,13 (gam) hỗn hợp X tác dụng với 7,52 (gam) hỗn hợp Y (có xúc tác H₂SO₄ đặc) thu được m (gam) hỗn hợp este (hiệu suất của các phản ứng este hoá đều bằng 80%). Giá trị của m là:

Đốt cháy hoàn toàn 0,1 (mol) este X thu được 0,3 (mol) CO₂ và 0,3 (mol) H₂O. Nếu cho 0,1 (mol) X tác dụng hết với NaOH thì thu được 8,2 (gam) muối. Công thức cấu tạo của X là:

Xà phòng hóa một hợp chất có công thức phân tử C₁₀H₁₄O₆ trong dung dịch NaOH (dư), thu được glixerol và hỗn hợp gồm ba muối (không có đồng phân hình học). Công thức của ba muối đó là:

Cho chất biến hóa: CH₃COOCH=CH₂

Các chất A, B, X lần lượt là:

Xà phòng hoá hoàn toàn 1,48 (gam) hỗn hợp hai este X, Y là đồng phân của nhau cần dùng hết 20 (ml) dung dịch NaOH 1M. Mặt khác khi đốt cháy hoàn toàn hỗn hợp hai este đó thì thu được khí CO₂ và H₂O với thể tích bằng nhau (ở cùng điều kiện). Công thức cấu tạo hai este đó là:

Chất nào có nhiệt độ sôi thấp nhất?

Thực hiện phản ứng este hóa hỗn hợp gồm 322,5 gam axit metacrylic và 150 gam ancol metylic với hiệu suất đạt 60%. Khối lượng metyl metacrylat thu được là:

Ở ruột non cơ thể người , nhờ tác dụng xúc tác của các enzim như lipaza và dịch mật chất béo bị thuỷ phân thành:

Thủy phân hoàn toàn 0,1 (mol) este X (chỉ chứa một loại nhóm chức) cần dùng vừa đủ 100 (gam) dung dịch NaOH 12%, thu được 20,4 (gam) muối của một axit hữu cơ và 9,2 (gam) một ancol. Biết rằng một trong hai chất tạo thành X là đơn chức. Công thức cấu tạo thu gọn của X là:

Công thức phân tử nào dưới đây không thể là của este :

Hỗn hợp X gồm C₂H₅OH, CH₃COOH và HCOOCH₃. Chia m gam hỗn hợp X thành ba phần bằng nhau:

- Phần 1: Cho tác dụng với Na có dư thu được 4,48 lít H₂ (đktc).

- Phần 2: Cho tác dụng với dung dịch NaOH 1M sau phản ứng thấy dùng hết 200 ml dung dịch.

- Phần 3: Đốt cháy hoàn toàn thu được 39,6g CO₂.

Giá trị của m là:

Cho 3,7 gam este no, đơn chức, mạch hở tác dụng hết với dung dịch KOH, thu được muối và 2,3 gam ancol etylic. Công thức của este là (Cho H = 1, C = 12, O = 16):

Hỗn hợp X gồm hai este no, đơn chức, mạch hở. Đốt cháy hoàn toàn một 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:

Để sản xuất xà phòng, người ta cho 0,178 tấn chất béo tác dụng với NaOH thu được glixerol và muối natri stearat duy nhất. Biết hiệu suất của quá trình sản xuất là 80%. Khối lượng muối natri stearat thu được là:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions that follow.

In the primary school, a child is in a comparatively simple setting and most of the time forms and relationships with one familiar teacher. On entering secondary school, a new world opens up and frequently it is a much more difficult world. The pupil soon learns to be less free in the way he speaks to teachers and even to his fellow pupils. He begins to lose radually the free and easy ways of the primary school, for he senses the need for a more cautious approach in the secondary school where there are older pupils. Secondary staff and pupils suffer from the pressures of academic work and seem to have less time to stop and talk. Teachers with specialist roles may see hundreds of children in a week, and a pupil may be able to form relationships with very few of the staff. He has to decide which adults are approachable; good schools will make clear to every young person from the first year what guidance and personal help is available - but whether the reality of life in the institution actually encourages requests for help is another matter. Adults often forget what a confusing picture school can offer to a child. He sees a great deal of movement, a great number of people - often rather frightening-looking people - and realizes that an increasing number of choices and decisions have to be made. As he progresses through the school the confusion may become less but the choices and decisions required will increase. The school will rightly expect the pupil to take the first steps to obtain the help he needs, for this is the pattern of adult of life for which he has to be prepared but all the time the opportunities for personal and group advice must be presented in a way which makes them easy to understand and within easy reach of pupils. 

Question: What will the school rightly expect the pupils to do?         

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions that follow.

In the primary school, a child is in a comparatively simple setting and most of the time forms and relationships with one familiar teacher. On entering secondary school, a new world opens up and frequently it is a much more difficult world. The pupil soon learns to be less free in the way he speaks to teachers and even to his fellow pupils. He begins to lose radually the free and easy ways of the primary school, for he senses the need for a more cautious approach in the secondary school where there are older pupils. Secondary staff and pupils suffer from the pressures of academic work and seem to have less time to stop and talk. Teachers with specialist roles may see hundreds of children in a week, and a pupil may be able to form relationships with very few of the staff. He has to decide which adults are approachable; good schools will make clear to every young person from the first year what guidance and personal help is available - but whether the reality of life in the institution actually encourages requests for help is another matter. Adults often forget what a confusing picture school can offer to a child. He sees a great deal of movement, a great number of people - often rather frightening-looking people - and realizes that an increasing number of choices and decisions have to be made. As he progresses through the school the confusion may become less but the choices and decisions required will increase. The school will rightly expect the pupil to take the first steps to obtain the help he needs, for this is the pattern of adult of life for which he has to be prepared but all the time the opportunities for personal and group advice must be presented in a way which makes them easy to understand and within easy reach of pupils. 

Question: The word “adults” in the second paragraph has the nearest meaning with ...................         

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions that follow.

In the primary school, a child is in a comparatively simple setting and most of the time forms and relationships with one familiar teacher. On entering secondary school, a new world opens up and frequently it is a much more difficult world. The pupil soon learns to be less free in the way he speaks to teachers and even to his fellow pupils. He begins to lose radually the free and easy ways of the primary school, for he senses the need for a more cautious approach in the secondary school where there are older pupils. Secondary staff and pupils suffer from the pressures of academic work and seem to have less time to stop and talk. Teachers with specialist roles may see hundreds of children in a week, and a pupil may be able to form relationships with very few of the staff. He has to decide which adults are approachable; good schools will make clear to every young person from the first year what guidance and personal help is available - but whether the reality of life in the institution actually encourages requests for help is another matter. Adults often forget what a confusing picture school can offer to a child. He sees a great deal of movement, a great number of people - often rather frightening-looking people - and realizes that an increasing number of choices and decisions have to be made. As he progresses through the school the confusion may become less but the choices and decisions required will increase. The school will rightly expect the pupil to take the first steps to obtain the help he needs, for this is the pattern of adult of life for which he has to be prepared but all the time the opportunities for personal and group advice must be presented in a way which makes them easy to understand and within easy reach of pupils. 

Question: How many pupils do teachers see in a week?         

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions that follow.

In the primary school, a child is in a comparatively simple setting and most of the time forms and relationships with one familiar teacher. On entering secondary school, a new world opens up and frequently it is a much more difficult world. The pupil soon learns to be less free in the way he speaks to teachers and even to his fellow pupils. He begins to lose radually the free and easy ways of the primary school, for he senses the need for a more cautious approach in the secondary school where there are older pupils. Secondary staff and pupils suffer from the pressures of academic work and seem to have less time to stop and talk. Teachers with specialist roles may see hundreds of children in a week, and a pupil may be able to form relationships with very few of the staff. He has to decide which adults are approachable; good schools will make clear to every young person from the first year what guidance and personal help is available - but whether the reality of life in the institution actually encourages requests for help is another matter. Adults often forget what a confusing picture school can offer to a child. He sees a great deal of movement, a great number of people - often rather frightening-looking people - and realizes that an increasing number of choices and decisions have to be made. As he progresses through the school the confusion may become less but the choices and decisions required will increase. The school will rightly expect the pupil to take the first steps to obtain the help he needs, for this is the pattern of adult of life for which he has to be prepared but all the time the opportunities for personal and group advice must be presented in a way which makes them easy to understand and within easy reach of pupils. 

Question: Who do the pupils make relationship with?         

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions that follow.

In the primary school, a child is in a comparatively simple setting and most of the time forms and relationships with one familiar teacher. On entering secondary school, a new world opens up and frequently it is a much more difficult world. The pupil soon learns to be less free in the way he speaks to teachers and even to his fellow pupils. He begins to lose radually the free and easy ways of the primary school, for he senses the need for a more cautious approach in the secondary school where there are older pupils. Secondary staff and pupils suffer from the pressures of academic work and seem to have less time to stop and talk. Teachers with specialist roles may see hundreds of children in a week, and a pupil may be able to form relationships with very few of the staff. He has to decide which adults are approachable; good schools will make clear to every young person from the first year what guidance and personal help is available - but whether the reality of life in the institution actually encourages requests for help is another matter. Adults often forget what a confusing picture school can offer to a child. He sees a great deal of movement, a great number of people - often rather frightening-looking people - and realizes that an increasing number of choices and decisions have to be made. As he progresses through the school the confusion may become less but the choices and decisions required will increase. The school will rightly expect the pupil to take the first steps to obtain the help he needs, for this is the pattern of adult of life for which he has to be prepared but all the time the opportunities for personal and group advice must be presented in a way which makes them easy to understand and within easy reach of pupils.   

Question: In this passage about secondary schools, the author is mainly concerned about ................         

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:

These days, photography is considered an art form. However, people did not always feel this way. It took one of the greatest photographers of all time to change public opinion about photography: Ansel Adams. Ansel Adams claimed that he knew his destiny when he first visited Yosemite, a national park, at the age of fourteen. Until then, the focus of his life had always been music; he had long dreamed of being a concert pianist, a career that would have required him to live an urban lifestyle. Instead, Adams found himself drawn to Yosemite and to other natural settings. Over time his love of photography became more influential than that of music. Contrary to the popular belief of the time, he believed photography to be an art form and often exhibited it as art. Due to his love of nature, Adams became devoted to the conservation of and access to wilderness. He believed that the American people needed to experience nature in all its glory. Adams felt that the experience of nature was a spiritual one, a view evidenced by many of his photographs.

Question 30: What can we infer about photographers before Adams' time?         

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:

These days, photography is considered an art form. However, people did not always feel this way. It took one of the greatest photographers of all time to change public opinion about photography: Ansel Adams. Ansel Adams claimed that he knew his destiny when he first visited Yosemite, a national park, at the age of fourteen. Until then, the focus of his life had always been music; he had long dreamed of being a concert pianist, a career that would have required him to live an urban lifestyle. Instead, Adams found himself drawn to Yosemite and to other natural settings. Over time his love of photography became more influential than that of music. Contrary to the popular belief of the time, he believed photography to be an art form and often exhibited it as art. Due to his love of nature, Adams became devoted to the conservation of and access to wilderness. He believed that the American people needed to experience nature in all its glory. Adams felt that the experience of nature was a spiritual one, a view evidenced by many of his photographs.

Question 31: According to the passage, which of the following made Adams want to become a photographer?         

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:

These days, photography is considered an art form. However, people did not always feel this way. It took one of the greatest photographers of all time to change public opinion about photography: Ansel Adams. Ansel Adams claimed that he knew his destiny when he first visited Yosemite, a national park, at the age of fourteen. Until then, the focus of his life had always been music; he had long dreamed of being a concert pianist, a career that would have required him to live an urban lifestyle. Instead, Adams found himself drawn to Yosemite and to other natural settings. Over time his love of photography became more influential than that of music. Contrary to the popular belief of the time, he believed photography to be an art form and often exhibited it as art. Due to his love of nature, Adams became devoted to the conservation of and access to wilderness. He believed that the American people needed to experience nature in all its glory. Adams felt that the experience of nature was a spiritual one, a view evidenced by many of his photographs.

Question 32: The word “destiny” in paragraph 2 is closest in meaning to _______.         

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:

These days, photography is considered an art form. However, people did not always feel this way. It took one of the greatest photographers of all time to change public opinion about photography: Ansel Adams. Ansel Adams claimed that he knew his destiny when he first visited Yosemite, a national park, at the age of fourteen. Until then, the focus of his life had always been music; he had long dreamed of being a concert pianist, a career that would have required him to live an urban lifestyle. Instead, Adams found himself drawn to Yosemite and to other natural settings. Over time his love of photography became more influential than that of music. Contrary to the popular belief of the time, he believed photography to be an art form and often exhibited it as art. Due to his love of nature, Adams became devoted to the conservation of and access to wilderness. He believed that the American people needed to experience nature in all its glory. Adams felt that the experience of nature was a spiritual one, a view evidenced by many of his photographs.

Question 33: According to the passage, photography has come to be recognized as an art form since _______.         

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions:

These days, photography is considered an art form. However, people did not always feel this way. It took one of the greatest photographers of all time to change public opinion about photography: Ansel Adams. Ansel Adams claimed that he knew his destiny when he first visited Yosemite, a national park, at the age of fourteen. Until then, the focus of his life had always been music; he had long dreamed of being a concert pianist, a career that would have required him to live an urban lifestyle. Instead, Adams found himself drawn to Yosemite and to other natural settings. Over time his love of photography became more influential than that of music. Contrary to the popular belief of the time, he believed photography to be an art form and often exhibited it as art. Due to his love of nature, Adams became devoted to the conservation of and access to wilderness. He believed that the American people needed to experience nature in all its glory. Adams felt that the experience of nature was a spiritual one, a view evidenced by many of his photographs.

Question 29: What is this passage primarily about?