Cho 1,62 gam nhôm vào 100 ml dung dịch chứa CuSO4 0,6M và Fe2(SO4)3 xM. Kết thúc phản ứng thu được 4,96 gam chất rắn gồm 2 kim loại. Giá trị của x là  

Kim loại tan trong dung dịch HCl là ?

Phản ứng nào sau đây đúng ?         

Cho hỗn hợp Al, Fe vào dung dịch chứa AgNO3 và Cu(NO3)2 được dung dịch X và chất rắn Y gồm 3 kim loại. Chất rắn Y gồm  

Hòa tan 7,8 gam hỗn hợp bột Al và Mg trong dung dịch HCl dư. Sau phản ứng khối lượng dung dịch tăng thêm 7,0 gam so với dung dịch HCl ban đầu. Khối lượng Al và Mg trong hỗn hợp ban đầu là ?        

Hỗn hợp X gồm FeCl2 và KCl có tỉ lệ mol tương ứng là 1 : 2. Hòa tan hoàn toàn 16,56 gam X vào nước dư thu được dung dịch Y. Cho dung dịch AgNO3 dư vào Y, kết thúc phản ứng thu được m gam kết tủa. Giá trị m là                   

Đốt cháy 28,6 gam hỗn hợp gồm Al, Zn, Mg thu được 44,6 gam hỗn hợp oxit. Hòa tan hết oxit trong dung dịch HCl thu được dung dịch D. Cô cạn dung dịch D thu m gam chất muối khan là:

Đốt cháy 11,9 gam hỗn hợp gồm Zn, Al trong khí Cl2 dư. Sau khi các phản ứng xảy ra hoàn toàn, thu được 40,3 gam hỗn hợp muối. Thể tích khí Cl2 (đktc) đã phản ứng là         

Cho các thí nghiệm sau:

(a) Cho kim loại Fe vào dung dịch CuCl₂.

(b) cho Fe(NO₃)₂ tác dụng với dung dịch HCl.

(c) Cho FeCO₃ tác dụng với dung dịch H_­2SO₄ loãng.

(d) Cho Fe₃O₄ tác dụng với dung dịch H₂SO₄ đặc, nóng, dư.

Số thí nghiệm tạo ra chất khí là:

X là kim loại phản ứng được với dung dịch H2SO4 loãng, Y là kim loại tác dụng được với dung dịch Fe(NO3)3. Hai kim loại X, Y lần lượt là:

Cho 1,62 gam nhôm vào 100 ml dung dịch chứa CuSO4 0,6M và Fe2(SO4)3 xM. Kết thúc phản ứng thu được 4,96 gam chất rắn gồm 2 kim loại. Giá trị của x 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:

                                                                  COLORS AND EMOTIONS

Colors are one of the most exciting experiences in life. I love them, and they are just as important to me as emotions are. Have you ever wondered how the two are so intimately related? Color directly affects your emotions. Color both reflects the current state of your emotions, and is something that you can use to improve or change your emotions. The color that you choose to wear either reflects your current state of being, or reflects the color or emotion that you need. The colors that you wear affect you much more than they affect the people around you. Of course they also affect anyone who comes in contact with you, but you are the one saturated with the color all day! I even choose items around me based on their color. In the morning, I choose my clothes based on the color or emotion I need for the day. So you can consciously use color to control the emotions that you are exposed to, which can help you to feel better. Color, sound and emotions are all vibrations. Emotions are literally energy in motion; they are meant to move and flow. This is the reason that real feelings are the fastest way to get your energy in motion. Also, flowing energy is exactly what creates healthy cells in your body. So, the fastest way to be healthy is to be open to your real feelings. Alternately, the fastest way to create disease is to inhibit your emotions.

Question: Which of the following can be most affected by color?         

Phát biểu nào sau đây đúng: Hiện tượng cộng hưởng chỉ xảy ra với dao động:

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:

                                                                  COLORS AND EMOTIONS

Colors are one of the most exciting experiences in life. I love them, and they are just as important to me as emotions are. Have you ever wondered how the two are so intimately related? Color directly affects your emotions. Color both reflects the current state of your emotions, and is something that you can use to improve or change your emotions. The color that you choose to wear either reflects your current state of being, or reflects the color or emotion that you need. The colors that you wear affect you much more than they affect the people around you. Of course they also affect anyone who comes in contact with you, but you are the one saturated with the color all day! I even choose items around me based on their color. In the morning, I choose my clothes based on the color or emotion I need for the day. So you can consciously use color to control the emotions that you are exposed to, which can help you to feel better. Color, sound and emotions are all vibrations. Emotions are literally energy in motion; they are meant to move and flow. This is the reason that real feelings are the fastest way to get your energy in motion. Also, flowing energy is exactly what creates healthy cells in your body. So, the fastest way to be healthy is to be open to your real feelings. Alternately, the fastest way to create disease is to inhibit your emotions.

Question: According to this passage, what do color, sound and emotions all have in common?         

 Một con lắc dao động cưỡng bức dưới tác dụng của lực điều hòa có tần số thay đổi được. Khi tần số là f₁ hoặc f₂ > f₁ thì biên độ dao động là A, Nếu tần số của lực cưỡng bức là  thì biên độ dao động là A', trong đó:         

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:

                                                                  COLORS AND EMOTIONS

Colors are one of the most exciting experiences in life. I love them, and they are just as important to me as emotions are. Have you ever wondered how the two are so intimately related? Color directly affects your emotions. Color both reflects the current state of your emotions, and is something that you can use to improve or change your emotions. The color that you choose to wear either reflects your current state of being, or reflects the color or emotion that you need. The colors that you wear affect you much more than they affect the people around you. Of course they also affect anyone who comes in contact with you, but you are the one saturated with the color all day! I even choose items around me based on their color. In the morning, I choose my clothes based on the color or emotion I need for the day. So you can consciously use color to control the emotions that you are exposed to, which can help you to feel better. Color, sound and emotions are all vibrations. Emotions are literally energy in motion; they are meant to move and flow. This is the reason that real feelings are the fastest way to get your energy in motion. Also, flowing energy is exactly what creates healthy cells in your body. So, the fastest way to be healthy is to be open to your real feelings. Alternately, the fastest way to create disease is to inhibit your emotions.

Question: What is the main idea of the passage?         

Chọn phát biểu sai. Dao động cưỡng bức có:         

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:

Some years ago, my daughter was studying English at a university on the south coast. One evening she phoned to tell me that what she really wanted to do was looking (31) ________the world, so she was looking into the possibility of working in another country. She had seen several (32) ________ in the newspaper for student teachers of English abroad, and she was interested in one in Italy, which she was desperate to visit. She decided that this would be a good way to achieve her ambition, so she was writing to apply for the job. The reply took a long time to arrive, but eventually she received a letter asking if she would go for an interview in London the following week. She was so excited that she immediately got in touch with the school owner and agreed to attend the interview. She was determined that nothing would prevent her (33) ________ doing what she had set out to do. A few days before the interview she had a very strange dream in which she gave birth to a beautiful baby. She was a little nervous and (34) ________about the dream and phoned to ask me what I thought it might mean. As I knew something about dreams, I was able to assure her that it only symbolized her (35) ________to do well in the interview. 

Question 34: 

Dao động duy trì là dao động mà người ta đã:         

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:

                                                                  COLORS AND EMOTIONS

Colors are one of the most exciting experiences in life. I love them, and they are just as important to me as emotions are. Have you ever wondered how the two are so intimately related? Color directly affects your emotions. Color both reflects the current state of your emotions, and is something that you can use to improve or change your emotions. The color that you choose to wear either reflects your current state of being, or reflects the color or emotion that you need. The colors that you wear affect you much more than they affect the people around you. Of course they also affect anyone who comes in contact with you, but you are the one saturated with the color all day! I even choose items around me based on their color. In the morning, I choose my clothes based on the color or emotion I need for the day. So you can consciously use color to control the emotions that you are exposed to, which can help you to feel better. Color, sound and emotions are all vibrations. Emotions are literally energy in motion; they are meant to move and flow. This is the reason that real feelings are the fastest way to get your energy in motion. Also, flowing energy is exactly what creates healthy cells in your body. So, the fastest way to be healthy is to be open to your real feelings. Alternately, the fastest way to create disease is to inhibit your emotions.

Question: The term “they” in paragraph 3 refers to________.         

Con lắc lò xo gồm hòn bi có khối lượng m, lò xo có độ cứng k. Tác dụng một ngoại lực điều hòa cưỡng bức biên độ F0 và tần số thì biên độ dao động ổn định của hệ là A1. Nếu giữ nguyên F0 và tăng tần số ngoại lực đến giá trị thì biên độ dao động ổn định của hệ là A2. So sánh A1 và A2 ta có: