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Câu 4:
Đun nóng 0,1 mol este đơn chức X với dung dịch NaOH (vừa đủ). Sau khi phản ứng xảy ra hoàn toàn, cô cạn dung dịch thu được ancol etylic và 8,2 gam muối khan. Công thức cấu tạo của X là A. C2H3 COOC 2H5 . B. C2H5 COOCH 3 . C. C2H5 COOC 2H3 . D. CH 3 COOC 2H Thủy phân hoàn toàn 8,8 gam este C4H8O2, thu được 4,6 gam ancol. Tên gọi của este là A. etyl axetat. B. metyl propionat. C. propyl axetat. D. isopropyl fomat. Mình xin cách giải ạ
Cho mình xin đáp án câu hỏi này với ạ
Vẽ đậu mầm. NL: Xin experience bắt slot của mn ạ!
20. Phân tích đa thức thành nhân tử a) $9x^{2}+6xy+y^{2}$ b) $6x-y-x^{2}$ c) $x^{2}+4y^{2}+4xy$
8 năm về trước tổng số tuổi của 3 cha con cộng lại là 45 tuổi . 8 năm sau , cha hơn con lớn 26 tuổi và hơn con bé 34 tuổi . Tính tuổi của mỗi người hiện nay NL:Có sơ đồ nhé!💝💝💝💝
Bài này làm sao ạ em không giải được ạ
You can do a few things to make homework less stressful. First, be sure you understand the assignment. Write it down in your notebook or day planner if you need to and don’t be afraid to ask questions about what is expected. It is much easier to take a minute to ask the teacher during or after class than to struggle to remember later that night! If you want, you can also ask how long the particular homework assignment should take to complete so you can plan your time. Second, use any extra time you have in school to work on your homework. Many schools have libraries that are specifically designed to allow students to study or get homework done. The more work you can get done in school, the less you will have to do that night. Third, pace yourself. If you don't finish your homework during school, think about how much you have left and what else is going on that day, and then plan your time. Most middle students should have between 1 and 3 hours of homework a night. If it is a heavy homework day, you will need to devote more time to homework. No one is expected to understand everything, and maybe you need some help. The first time to turn for help is your teacher. But what if you don't feel comfortable with your teacher? If you are in a big enough school, there may be other teachers who teach the same subject. Speak to other teachers directly and you may be in task. Sometimes it just helps to have someone explain something in a different way. Moreover, you might also be able to get some help from another student. If there is someone you like who is a good student, think about asking that person if you can study together. Question 29: What is the most important thing you should do when you get your assignment? A. to know when you hand it in B. to understand it and its requirements C. to know how long it takes to complete it D. to remember it in order to plan the time Question 30: If you have any free time left at school, you should ______. A. use it to do your homework in the library B. spend time with your friends C. use it to understand the assignment D. use it to make your day planner Question 31: When students need some help, they should ______. A. never ask other teachers because it will hurt their own teachers B. always turn to their own teachers for help C. ask any good students at the subject in your school D. go to their teachers or other teachers teaching the same subject Question 32: The main idea of the first three paragraphs is ______. A. to get help when you need it B. to do homework immediately C. to create a homework plan D. to ask your teachers for more explanation
cảm ơn nhaaaaaaaaaaa không cần chi tiết đâu ạ
nêu kinh độ , vĩ độ của cột cờ Hà Nội nhanh cho hn
Living in a city has a number of drawbacks. Firstly, there is the problem of traffic (25) _______and traffic accidents. The increase in population and the increasing number of vehicles have (26) ______many accidents to happen every day. Secondly, air pollution (27) _______affects people’s health, and is also has a bad influence on the environment. More and more city dwellers suffer from coughing or (28) _______ problems. Thirdly, the city is noisy, even at night. Noise pollution comes from the traffic and from construction sites. Buildings are always being knocked down and rebuilt. These factors contribute to making city life more difficult for its residents. Question 25: A. calm B. jams C. light D. legacy Question 26: A. caused B. made C. done D. got Question 27: A. actively B. negatively C. positively D. weakly Question 28: A. breathe B. breathed C. to breathe D. breathing
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