Danh sách câu hỏi ( Có 2,554,362 câu hỏi trên 51,088 trang )

Phản ứng este hóa – điều chế este

Cho các este sau đây; vinyl axetat (1), metyl axetat (2), benzyl fomat (3), phenyl axetat (4), etyl propionat (5). Số este có thể điều chế trực tiếp bằng phản ứng của axit và ancol tương ứng (có H2SO4 đặc làm xúc tác) là

Hóa học Lớp 12

Xem chi tiết 13.2 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Trong các thí nghiệm sau đây, số thí nghiệm xảy ra sự oxi hóa kim loại? (1). Điện phân CaCl2 nóng chảy. (2). Cho kim loại Zn vào dung dịch NaOH. (3). Cho AgNO3 vào dung dịch Fe(NO3)2. (4). Cho Fe3O4 vào dung dịch HI. (5). Cho FeO vào dung dịch HNO3 loãng dư. (6). Cho luồng khí H2 đi qua ống sứ đựng CuO nung nóng. (7). Đốt thanh sắt ngoài không khí. (8). Để một cái nồi bằng gang ngoài không khí ẩm. (9). Một sợi dây truyền bằng Ag bị đốt cháy.

Hóa học Tốt nghiệp THPT

Xem chi tiết 1.9 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions. Alice and Charles did not decide to move to a bigger house until after the birth of their second child.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 54.5 K lượt xem 6 năm trước

Đề thi thử THPTQG năm 2019 chuẩn cấu trúc của bộ giáo dục có đáp án (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question. Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings. People need to communicate in order to _______ .

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 410 lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions. She phoned him early in the morning. She wanted to talk to him before he left for work.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 5.1 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Cho các phát biểu sau: (1)Phenol có tính axit mạnh hơn ancol nhưng vẫn không làm hóa đỏ quỳ tím. (2)Phenol được dùng để điều chế nhựa phenol-fomadehit,thuốc diệt cỏ phẩm nhuộm,chất diệt nấm mốc.... (3)Phản ứng thế brom vào vòng thơm của phenol dễ hơn phản ứng thế của brom vào vòng benzen. (4)Nếu cho dung dịch HNO3 vào phenol ta sẽ thu được kết tủa trắng của axit picric Số phát biêu đúng là:

Hóa học Tốt nghiệp THPT

Xem chi tiết 5.1 K lượt xem 6 năm trước

Đề thi thử THPTQG năm 2019 chuẩn cấu trúc của bộ giáo dục có đáp án (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question. Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings. What is the best title for the passage?

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 1 K lượt xem 6 năm trước

Xác định đồng phân từ phản ứng tráng bạc

Este X có công thức phân tử C5H8O2 khi tác dụng với NaOH tạo ra 2 sản phẩm đều có khả năng tham gia phản ứng tráng gương. Số chất X thỏa mãn điều kiện trên là

Hóa học Lớp 12

Xem chi tiết 3.9 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions. You should not send money to us by post under any circumstances.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 15.6 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Cho các thí nghiệm sau : (1) Đun nóng nước cứng tạm thời. (2) Cho phèn chua vào dung dịch Ba(OH)2 dư. (3) Cho dung dịch NaOH dư vào dung dịch AlCl3. (4) Cho khí CO2 dư vào dung dịch NaAlO2. (5) Cho khí NH3 dư vào dung dịch AlCl3. (6) Cho K2CO3 vào dung dịch AlCl3. Số thí nghiệm thu được kết tủa là?

Hóa học Tốt nghiệp THPT

Xem chi tiết 581 lượt xem 6 năm trước

Đề thi thử THPTQG năm 2019 chuẩn cấu trúc của bộ giáo dục có đáp án (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question. Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings. Which of the following best summarizes this passage?

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 2.6 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions. “I am in a bit of hurry, but I’ll ring you tomorrow”, he said.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 14.9 K lượt xem 1 năm trước

Phản ứng este hóa – điều chế este

Trong số các este sau, các este nào có thể điều chế trực tiếp từ axit và ancol tương ứng ? HCOO-CH=CH-CH3 (1) ; HCOO-CH2-CH=CH2 (2) ; HCOO-C(CH3)=CH2 (3); CH3COO-CH=CH2 (4); CH2=CH-COO-CH3 (5) ; CH3COOC6H5 (6)

Hóa học Lớp 12

Xem chi tiết 24.1 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Có 5 hỗn hợp, mỗi hỗn hợp gồm 2 chất rắn có số mol bằng nhau: Na2Ovà Al2O3; Cu và Fe2(SO4)3; KHSO4 và KHCO3; BaCl2 và CuSO4; Fe(NO3)2và AgNO3. Số hỗn hợp có thể tan hoàn toàn trong nước (dư) chỉ tạo ra các chất tan trong nước là

Hóa học Tốt nghiệp THPT

Xem chi tiết 385 lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions. I would prefer you to deliver the sofa on Saturday.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 44.5 K lượt xem 6 năm trước

Đề thi thử THPTQG năm 2019 chuẩn cấu trúc của bộ giáo dục có đáp án (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question. Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings. The word “wink” in the second paragraph means most nearly the same as _______ .

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 722 lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 questions Albert Einstein was such brilliant (A) a scientist that many of his colleagues (B) had to study (C) for several years (D) in order to form opinions about his theories.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 26.5 K lượt xem 6 năm trước

Phản ứng este hóa – điều chế este

Trong số các Este mạch hở C4H6O2: HCOO-CH=CH-CH3 (1) HCOO-CH2-CH=CH2 (2) HCOO-C(CH3)=CH2 (3) CH3COO-CH=CH2 (4) CH2=CH-COO-CH3 (5) Các este có thể điều chế trực tiếp từ axit và ancol là:

Hóa học Lớp 12

Xem chi tiết 2.4 K lượt xem 6 năm trước

Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 19)

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 23 to 27. LIFE OF EARTH IN 2110 The worst prediction for the next century (23) _______ the weather. Many people think that global warming will cause important environmental changes. There is scientific evidence that suggests cities on the coast may disappear if the sea level (24) _ There is better news regarding health. Medical advances mean that people will live longer. Doctors will be more successfully diagnosing an illness (25) _ of new technology. Infective diseases will disappear in many areas of the world and new drugs will be how to treat muscular aches and pains. Futuristic organ transplants will be easier. Technological progress will give experts the (26) _ to manufacture invisibility cloaks, which may be (27) _______ the market before the end of the century. Điền vào ô 27

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 1.8 K lượt xem 6 năm trước

Đề thi thử THPTQG năm 2019 chuẩn cấu trúc của bộ giáo dục có đáp án (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question. Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings. Sign language is said to be very picturesque and exact and can be used internationally EXCEPT for _______ .

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 816 lượt xem 6 năm trước

Xác định đồng phân từ phản ứng tráng bạc

Thủy phân este X (C4H8O2) thu được sản phẩm có phản ứng tráng bạc. Số công thức cấu tạo của X thỏa mãn tính chất trên là

Hóa học Lớp 12

Xem chi tiết 59.2 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 questions. Nearly (A) chemical agents are harmful (B) to living tissues (C) if enough of them is taken (D).

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 10.7 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Có các phát biểu sau: 1) Hợp chất hữu cơ nhất thiết phải có cacbon và hidro. 2) Các hidrocacbon thơm đều có công thức chung là CnH2n+6với . 3) Penta-1,3-đien có đồng phân hình học cis-trans. 4) Isobutan tác dụng với Cl2 chiếu sáng theo tỉ lệ mol 1 : 1 chỉ thu được 1 sản phẩm hữu cơ. 5) Hidrocacbon có công thức phân tử C4H8 có 5 đồng phân cấu tạo. Số phát biểu đúng là

Hóa học Tốt nghiệp THPT

Xem chi tiết 756 lượt xem 6 năm trước

Đề thi thử THPTQG năm 2019 chuẩn cấu trúc của bộ giáo dục có đáp án (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question. Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings. The word “these” I the first paragraph refers to _______ .

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 852 lượt xem 6 năm trước

Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 19)

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 23 to 27. LIFE OF EARTH IN 2110 The worst prediction for the next century (23) _______ the weather. Many people think that global warming will cause important environmental changes. There is scientific evidence that suggests cities on the coast may disappear if the sea level (24) _ There is better news regarding health. Medical advances mean that people will live longer. Doctors will be more successfully diagnosing an illness (25) _ of new technology. Infective diseases will disappear in many areas of the world and new drugs will be how to treat muscular aches and pains. Futuristic organ transplants will be easier. Technological progress will give experts the (26) _ to manufacture invisibility cloaks, which may be (27) _______ the market before the end of the century. Điền vào ô 26

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 1.8 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 questions. The Green Garden Restaurant uses fresh produce (A) on their (B) dishes, much (C) of which the owners (D) grow in their own garden.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 13.5 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

X, Y là hai hợp chất hữu cơ đơn chức phân tử chỉ chứa C, H, O. Khi đốt cháy X, Y với số mol bằng nhau hoặc khối lượng bằng nhau đều thu được CO2với tỉ lệ mol tương ứng 2 : 3 và H2O với tỉ lệ mol tương ứng 1 : 2. Số cặp chất X, Y thỏa mãn là

Hóa học Tốt nghiệp THPT

Xem chi tiết 411 lượt xem 6 năm trước

Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 19)

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 23 to 27. LIFE OF EARTH IN 2110 The worst prediction for the next century (23) _______ the weather. Many people think that global warming will cause important environmental changes. There is scientific evidence that suggests cities on the coast may disappear if the sea level (24) _ There is better news regarding health. Medical advances mean that people will live longer. Doctors will be more successfully diagnosing an illness (25) _ of new technology. Infective diseases will disappear in many areas of the world and new drugs will be how to treat muscular aches and pains. Futuristic organ transplants will be easier. Technological progress will give experts the (26) _ to manufacture invisibility cloaks, which may be (27) _______ the market before the end of the century. Điền vào ô 25

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 4.4 K lượt xem 6 năm trước

Đề thi thử THPTQG năm 2019 chuẩn cấu trúc của bộ giáo dục có đáp án (Đề số 23)

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each question. Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally, spelling, however, cannot. Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a system of raised dots read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warm, and instruct people. While verbalization is most common form of language, other systems and techniques also express human thoughts and feelings. Which form other than oral speech would be the most commonly used among blind people?

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 769 lượt xem 6 năm trước

Xác định đồng phân từ phản ứng tráng bạc

Thủy phân este mạch hở X có công thức phân tử C4H6O2 thu được các sản phẩm đều tham gia phản ứng tráng bạc. Số công thức cấu tạo phù hợp với X là

Hóa học Lớp 12

Xem chi tiết 95.3 K lượt xem 6 năm trước

Tổng hợp bài tập thí nghiệm Hóa học từ đề thi Đại học có đáp án (P3)

Kết quả thí nghiệm của các dung dịch X, Y, Z, T với thuốc thử được ghi lại trong bảng sau: Các dung dịch X, Y, Z, T lần lượt là

Hóa học Tốt nghiệp THPT

Xem chi tiết 381 lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 following questions. It’s often said that we team things at the wrong time. University students frequently do the minimum of work because they’re crazy about a good social life instead. Children often scream before their piano practice 5 because it’s so boring. They have to be given gold stars and medals to be persuaded to swim, or have to be bribed to take exams. But the story is different when you’re older. Over the years, I’ve done my share of adult learning. At 30, I went to a college and did courses in History and English. It was an amazing experience. For starters, I was paying, so there was no reason to be late - I was the one frowning and drumming my fingers if the tutor was late, not the other way round. Indeed, if I could persuade him to linger for an extra five minutes, it was a bonus, not a nuisance. I wasn’t frightened to ask questions, and homework was a pleasure not a pain. When I passed an exam, I had a big meal, not for my parents or my teachers. The satisfaction I got was entirely personal. Some people fear going back to school because they worry that their brains have got rusty. But the joy is that, although some parts have rusted up, your brain has learnt all kinds of other things since you were young. It has learnt to think independently and flexibly and is much better at relating one thing to another. What you lose in the rust department, you gain in the maturity department. In some ways, age is a positive plus. For instance, when you’re older, you get less frustrated. Experience has told you that, if you’re calm and simply do something carefully again and again, eventually you’ll get the hang of it. The confidence you have in other areas - from being able to drive a car, perhaps - means that if you can’t, say, build a chair instantly, you don’t, like a child, want to destroy your first pathetic attempts. Maturity tells you that you will, with application, eventually get there. I hated piano lessons at school, but I was good at music. And coming back to it, with a teacher who could explain why certain exercises were useful and with musical concepts that, at the age of ten. I could never grasp, was magical. Initially, I did feel a bit strange, thumping out a piece that I’d played for my school exams, with just as little comprehension of what the composer intended as I’d had all those years before. But soon, complex emotions that I never knew poured out from my fingers, and suddenly I could understand why practice makes perfect. It is implied in the last paragraph that when you learn later in life, you _____

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 395 lượt xem 6 năm trước

Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 19)

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 23 to 27. LIFE OF EARTH IN 2110 The worst prediction for the next century (23) _______ the weather. Many people think that global warming will cause important environmental changes. There is scientific evidence that suggests cities on the coast may disappear if the sea level (24) _ There is better news regarding health. Medical advances mean that people will live longer. Doctors will be more successfully diagnosing an illness (25) _ of new technology. Infective diseases will disappear in many areas of the world and new drugs will be how to treat muscular aches and pains. Futuristic organ transplants will be easier. Technological progress will give experts the (26) _ to manufacture invisibility cloaks, which may be (27) _______ the market before the end of the century. Điền vào ô 24

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 1.4 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Cho các chất Al, AlCl3, Zn(OH)2, NH4HCO3, KHSO4, NaHSO4, NaHS, Fe(NO3)2. Số chất vừa phản ứng với dung dịch NaOH vừa phản ứng với dung dịch HCl là:

Hóa học Tốt nghiệp THPT

Xem chi tiết 405 lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 following questions. It’s often said that we team things at the wrong time. University students frequently do the minimum of work because they’re crazy about a good social life instead. Children often scream before their piano practice 5 because it’s so boring. They have to be given gold stars and medals to be persuaded to swim, or have to be bribed to take exams. But the story is different when you’re older. Over the years, I’ve done my share of adult learning. At 30, I went to a college and did courses in History and English. It was an amazing experience. For starters, I was paying, so there was no reason to be late - I was the one frowning and drumming my fingers if the tutor was late, not the other way round. Indeed, if I could persuade him to linger for an extra five minutes, it was a bonus, not a nuisance. I wasn’t frightened to ask questions, and homework was a pleasure not a pain. When I passed an exam, I had a big meal, not for my parents or my teachers. The satisfaction I got was entirely personal. Some people fear going back to school because they worry that their brains have got rusty. But the joy is that, although some parts have rusted up, your brain has learnt all kinds of other things since you were young. It has learnt to think independently and flexibly and is much better at relating one thing to another. What you lose in the rust department, you gain in the maturity department. In some ways, age is a positive plus. For instance, when you’re older, you get less frustrated. Experience has told you that, if you’re calm and simply do something carefully again and again, eventually you’ll get the hang of it. The confidence you have in other areas - from being able to drive a car, perhaps - means that if you can’t, say, build a chair instantly, you don’t, like a child, want to destroy your first pathetic attempts. Maturity tells you that you will, with application, eventually get there. I hated piano lessons at school, but I was good at music. And coming back to it, with a teacher who could explain why certain exercises were useful and with musical concepts that, at the age of ten. I could never grasp, was magical. Initially, I did feel a bit strange, thumping out a piece that I’d played for my school exams, with just as little comprehension of what the composer intended as I’d had all those years before. But soon, complex emotions that I never knew poured out from my fingers, and suddenly I could understand why practice makes perfect. It can be inferred from paragraph 4 that maturity is a positive plus in the learning process because adult learners ________.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 475 lượt xem 6 năm trước

Phản ứng este hóa – điều chế este

Dãy hoá chất nào sau đây cần sử dụng để điều chế được benzyl axetat

Hóa học Lớp 12

Xem chi tiết 6.1 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 following questions. It’s often said that we team things at the wrong time. University students frequently do the minimum of work because they’re crazy about a good social life instead. Children often scream before their piano practice 5 because it’s so boring. They have to be given gold stars and medals to be persuaded to swim, or have to be bribed to take exams. But the story is different when you’re older. Over the years, I’ve done my share of adult learning. At 30, I went to a college and did courses in History and English. It was an amazing experience. For starters, I was paying, so there was no reason to be late - I was the one frowning and drumming my fingers if the tutor was late, not the other way round. Indeed, if I could persuade him to linger for an extra five minutes, it was a bonus, not a nuisance. I wasn’t frightened to ask questions, and homework was a pleasure not a pain. When I passed an exam, I had a big meal, not for my parents or my teachers. The satisfaction I got was entirely personal. Some people fear going back to school because they worry that their brains have got rusty. But the joy is that, although some parts have rusted up, your brain has learnt all kinds of other things since you were young. It has learnt to think independently and flexibly and is much better at relating one thing to another. What you lose in the rust department, you gain in the maturity department. In some ways, age is a positive plus. For instance, when you’re older, you get less frustrated. Experience has told you that, if you’re calm and simply do something carefully again and again, eventually you’ll get the hang of it. The confidence you have in other areas - from being able to drive a car, perhaps - means that if you can’t, say, build a chair instantly, you don’t, like a child, want to destroy your first pathetic attempts. Maturity tells you that you will, with application, eventually get there. I hated piano lessons at school, but I was good at music. And coming back to it, with a teacher who could explain why certain exercises were useful and with musical concepts that, at the age of ten. I could never grasp, was magical. Initially, I did feel a bit strange, thumping out a piece that I’d played for my school exams, with just as little comprehension of what the composer intended as I’d had all those years before. But soon, complex emotions that I never knew poured out from my fingers, and suddenly I could understand why practice makes perfect. All of the following are true about adult learning EXCEPT_____.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 669 lượt xem 6 năm trước

Xác định đồng phân từ phản ứng tráng bạc

Số đồng phân mạch hở của C3H4O2 có khả năng tham gia phản ứng tráng bạc là

Hóa học Lớp 12

Xem chi tiết 5.2 K lượt xem 6 năm trước

Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 19)

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 23 to 27. LIFE OF EARTH IN 2110 The worst prediction for the next century (23) _______ the weather. Many people think that global warming will cause important environmental changes. There is scientific evidence that suggests cities on the coast may disappear if the sea level (24) _ There is better news regarding health. Medical advances mean that people will live longer. Doctors will be more successfully diagnosing an illness (25) _ of new technology. Infective diseases will disappear in many areas of the world and new drugs will be how to treat muscular aches and pains. Futuristic organ transplants will be easier. Technological progress will give experts the (26) _ to manufacture invisibility cloaks, which may be (27) _______ the market before the end of the century. Điền vào ô 23

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 845 lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Cho các chất: C2H5OH, CH3COOH; C2H2; C2H4. Có bao nhiêu chất sinh ra từ CH3CHO bằng một phản ứng.

Hóa học Tốt nghiệp THPT

Xem chi tiết 453 lượt xem 6 năm trước

Tổng hợp bài tập thí nghiệm Hóa học từ đề thi Đại học có đáp án (P3)

Tiến hành các thí nghiệm như hình vẽ sau (các thí nghiệm được thực hiện trong cùng điều kiện): Đinh sắt trong cốc nào bị ăn mòn nhanh nhất?

Hóa học Tốt nghiệp THPT

Xem chi tiết 2.2 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 following questions. It’s often said that we team things at the wrong time. University students frequently do the minimum of work because they’re crazy about a good social life instead. Children often scream before their piano practice 5 because it’s so boring. They have to be given gold stars and medals to be persuaded to swim, or have to be bribed to take exams. But the story is different when you’re older. Over the years, I’ve done my share of adult learning. At 30, I went to a college and did courses in History and English. It was an amazing experience. For starters, I was paying, so there was no reason to be late - I was the one frowning and drumming my fingers if the tutor was late, not the other way round. Indeed, if I could persuade him to linger for an extra five minutes, it was a bonus, not a nuisance. I wasn’t frightened to ask questions, and homework was a pleasure not a pain. When I passed an exam, I had a big meal, not for my parents or my teachers. The satisfaction I got was entirely personal. Some people fear going back to school because they worry that their brains have got rusty. But the joy is that, although some parts have rusted up, your brain has learnt all kinds of other things since you were young. It has learnt to think independently and flexibly and is much better at relating one thing to another. What you lose in the rust department, you gain in the maturity department. In some ways, age is a positive plus. For instance, when you’re older, you get less frustrated. Experience has told you that, if you’re calm and simply do something carefully again and again, eventually you’ll get the hang of it. The confidence you have in other areas - from being able to drive a car, perhaps - means that if you can’t, say, build a chair instantly, you don’t, like a child, want to destroy your first pathetic attempts. Maturity tells you that you will, with application, eventually get there. I hated piano lessons at school, but I was good at music. And coming back to it, with a teacher who could explain why certain exercises were useful and with musical concepts that, at the age of ten. I could never grasp, was magical. Initially, I did feel a bit strange, thumping out a piece that I’d played for my school exams, with just as little comprehension of what the composer intended as I’d had all those years before. But soon, complex emotions that I never knew poured out from my fingers, and suddenly I could understand why practice makes perfect. In paragraph 3, the word “rusty” means____.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 1.2 K lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Tiến hành các thí nghiệm: (1) Cho khí NH3 tác dụng với CuO đun nóng. (2)Sục khí O3 vào dung dịch KI. (3) Cho Na vào dung dịch CuSO4. (4) Đun nóng dung dịch bão hòa của NaNO2 và NH4Cl. (5) Sục khí Cl2 vào H2S. Số thí nghiệm tạo ra đơn chất là

Hóa học Tốt nghiệp THPT

Xem chi tiết 1.1 K lượt xem 6 năm trước

Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 19)

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. Looking down at the coral reef, we saw _____________ of tiny, multi-coloured fish.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 680 lượt xem 6 năm trước

Phản ứng este hóa – điều chế este

Cho hợp chất p-HO-C6H4-CH2OH tác dụng với lượng dư axit axetic có H2SO4 đặc làm xúc tác, đun nóng. Giả thiết phản ứng xảy ra hoàn toàn. Vậy sản phẩm tạo ra là

Hóa học Lớp 12

Xem chi tiết 4.1 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 following questions. It’s often said that we team things at the wrong time. University students frequently do the minimum of work because they’re crazy about a good social life instead. Children often scream before their piano practice 5 because it’s so boring. They have to be given gold stars and medals to be persuaded to swim, or have to be bribed to take exams. But the story is different when you’re older. Over the years, I’ve done my share of adult learning. At 30, I went to a college and did courses in History and English. It was an amazing experience. For starters, I was paying, so there was no reason to be late - I was the one frowning and drumming my fingers if the tutor was late, not the other way round. Indeed, if I could persuade him to linger for an extra five minutes, it was a bonus, not a nuisance. I wasn’t frightened to ask questions, and homework was a pleasure not a pain. When I passed an exam, I had a big meal, not for my parents or my teachers. The satisfaction I got was entirely personal. Some people fear going back to school because they worry that their brains have got rusty. But the joy is that, although some parts have rusted up, your brain has learnt all kinds of other things since you were young. It has learnt to think independently and flexibly and is much better at relating one thing to another. What you lose in the rust department, you gain in the maturity department. In some ways, age is a positive plus. For instance, when you’re older, you get less frustrated. Experience has told you that, if you’re calm and simply do something carefully again and again, eventually you’ll get the hang of it. The confidence you have in other areas - from being able to drive a car, perhaps - means that if you can’t, say, build a chair instantly, you don’t, like a child, want to destroy your first pathetic attempts. Maturity tells you that you will, with application, eventually get there. I hated piano lessons at school, but I was good at music. And coming back to it, with a teacher who could explain why certain exercises were useful and with musical concepts that, at the age of ten. I could never grasp, was magical. Initially, I did feel a bit strange, thumping out a piece that I’d played for my school exams, with just as little comprehension of what the composer intended as I’d had all those years before. But soon, complex emotions that I never knew poured out from my fingers, and suddenly I could understand why practice makes perfect. The phrase “For starters” in paragraph 2 could best be replaced by ______

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 591 lượt xem 6 năm trước

500 bài tập lí thuyết Hóa Học nâng cao có lời giải (P4)

Cho các phát biểu: (1) Protein bị thủy phân khi đun nóng với dung dịch axit, dung dịch bazơ hoặc nhờ xúc tác của enzim. (2) Nhỏ vài giọt dung dịch axit nitric đặc vào ống nghiệp đựng dung dịch lòng trắng trứng (anbumin) thì có kết tủa vàng. (3) Hemoglobin của máu là protein dạng hình cầu. (4) Dung dịch protein có phản ứng màu biure. (5) Protein đông tụ khi cho axit, bazơ hoặc khi đun nóng. Số phát biểu đúng là:

Hóa học Tốt nghiệp THPT

Xem chi tiết 44.7 K lượt xem 6 năm trước

Đề thi thử thpt quốc gia 2019 môn tiếng anh (Đề số 19)

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions. I would like to _____________ my gratitude to everyone for their hard work.

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 14.4 K lượt xem 6 năm trước

Tổng hợp đề luyện thi Đại Học môn Tiếng Anh có lời giải(Đề số 12)

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 following questions. It’s often said that we team things at the wrong time. University students frequently do the minimum of work because they’re crazy about a good social life instead. Children often scream before their piano practice 5 because it’s so boring. They have to be given gold stars and medals to be persuaded to swim, or have to be bribed to take exams. But the story is different when you’re older. Over the years, I’ve done my share of adult learning. At 30, I went to a college and did courses in History and English. It was an amazing experience. For starters, I was paying, so there was no reason to be late - I was the one frowning and drumming my fingers if the tutor was late, not the other way round. Indeed, if I could persuade him to linger for an extra five minutes, it was a bonus, not a nuisance. I wasn’t frightened to ask questions, and homework was a pleasure not a pain. When I passed an exam, I had a big meal, not for my parents or my teachers. The satisfaction I got was entirely personal. Some people fear going back to school because they worry that their brains have got rusty. But the joy is that, although some parts have rusted up, your brain has learnt all kinds of other things since you were young. It has learnt to think independently and flexibly and is much better at relating one thing to another. What you lose in the rust department, you gain in the maturity department. In some ways, age is a positive plus. For instance, when you’re older, you get less frustrated. Experience has told you that, if you’re calm and simply do something carefully again and again, eventually you’ll get the hang of it. The confidence you have in other areas - from being able to drive a car, perhaps - means that if you can’t, say, build a chair instantly, you don’t, like a child, want to destroy your first pathetic attempts. Maturity tells you that you will, with application, eventually get there. I hated piano lessons at school, but I was good at music. And coming back to it, with a teacher who could explain why certain exercises were useful and with musical concepts that, at the age of ten. I could never grasp, was magical. Initially, I did feel a bit strange, thumping out a piece that I’d played for my school exams, with just as little comprehension of what the composer intended as I’d had all those years before. But soon, complex emotions that I never knew poured out from my fingers, and suddenly I could understand why practice makes perfect. The writer’s main point in paragraph 2 is to show that as people grow up _____

Tiếng Anh Tốt nghiệp THPT

Xem chi tiết 424 lượt xem 6 năm trước

Xác định đồng phân từ phản ứng tráng bạc

Cho hợp chất X có công thức C2HxOy (y > 0) có khối lượng phân tử nhỏ hơn 62. Có tối đa mấy chất X mà khi phản ứng với dung dịch AgNO3 trong NH3 thu được kết tủa ?

Hóa học Lớp 12

Xem chi tiết 4.3 K lượt xem 6 năm trước

Lớp 12

Lớp 11

Lớp 10

Ôn vào 10

Lớp 9

Lớp 8

Lớp 7

Lớp 6

Ôn vào 6

Lớp 5

Lớp 4

Lớp 3

Lớp 2

Lớp 1

Đại học

ĐGNL - ĐGTD

Tốt nghiệp THPT

Ôn vào 10

Ôn vào 6

V-ACT

HSA

TSA

SPT

Toán

Văn

Tiếng Anh

Vật lý

Hóa học

Sinh học

Lịch sử

Địa lý

Giáo dục Kinh tế và Pháp luật

Tin học

Công nghệ

Toán

Văn

Tiếng Anh

Vật lí

Hóa học

Sinh học

Lịch sử

Địa lí

Giáo dục Kinh tế và Pháp luật

Tin học

Công nghệ

Toán

Văn

Tiếng Anh

Vật lí

Hóa học

Sinh học

Lịch sử

Địa lí

Giáo dục Kinh tế và Pháp luật

Tin học

Công nghệ

Toán

Văn

Tiếng Anh

Vật lý

Hóa học

Sinh học

Lịch sử

Địa lí

Giáo dục Kinh tế và Pháp luật

Tin học

Công nghệ

Toán

Văn

Tiếng Anh

Vật lý

Hóa học

Sinh học

Khoa học tự nhiên

Tin học

Lịch sử

Địa lí

Toán

Văn

Tiếng Anh