Một vật có khối lương 3kg được đặt ở một vị trí sâu 2m so với mặt đất trong trọng trường. Tính thế năng tại đó. Chọn mốc thế năng tại mặt đất

Cho 16,8g hỗn hợp X gồm Cu,Mg,Fe tác dụng với clo dư ở nhiệt độ cao đến khi các phản ứng xảy ra hoàn toàn thu được 48,75g hh rắn. Mặt khác, 0.8 mol hh X tác dụng vừa đủ với 600ml đ HCl 2M. Tính số mol mỗi kim loại có trong 16,8g hh X.

READING PASSAGE 1 MEET THE ANCESTORS What makes you who you are? Part of the answer is in your family's past. Become a detective and find clues to your family history. 1. When you look in the mirror, do you see your father's smile? Maybe you take after your mother or look like a grandparent? That's because of DNA. Our DNA contains genes that make each person in the world different - no two people look, think or act the same. We pass down our genes through generations. Scientists can test your DNA to find out which part of the world your ancestors were from. 2. Your family's history may be a mystery to you, but there's a way to find out about it. It's called genealogy, and it's the study of the people you are related to. Genealogy helps you put together your family history. It starts with the relatives you know, such as parents and grandparents, and then you can learn about ancestors who lived and died before you were born. 3. It isn't difficult to learn about your past. You can begin by asking your relatives questions about your ancestors. While you are talking with family members, take notes. This helps you organise any information you get. Make sure you write down any names, dates or places people mention. Then you can draw a family tree with your name at the top. Then you would add all the relatives from you to your great grandparents so you can see how everyone is related. 4. If there any blank boxes in your tree it's time for some detective work! Many people begin at a library where they can look for family names in old newspapers. Public records are usually a very good thing to look at too. They have information about births, marriages and death certificates too. Some records show when people moved to a country. Sometimes, records tell you where people went to school and what their job was. You can also search the Internet. With every bit of research that you do, you are discovering your family's history. Task 1: Look at the sentences below about studying your family history. Read the text to decide if each sentence is correct or incorrect. Write T (True) or F (False). 1. We look the way we do because of the genes in our DNA. 2. A DNA test can show where in the world our ancestors lived. 3. You can find out the number of relatives you have in a DNA test. 4. Genealogy is the history of our past and present family members. 5. Relatives who are alive could have information about ancestors. 6. A family tree shows how you are relatedto other people in your family. 7. A detective can help you to find information about your family. 8. It is possible to buy old newspapers at some libraries. 9. Public records tell you when people were born. 10. The text says that websites can help you find information about your ancestors. Task 2: Find the underlined words in the text and think about what they mean. Then circle the correct meanings below. 1. take after: to follow somebody / to be like somebody 2. look like: to have a similar appearance / to seethings you enjoy 3. pass down: transfer to / respect the next generation 4. relative: family member / close friend 5. find out: to take outside / to discover or learn 6. look for: to be similar to / to try to find

1. We ________ to each other since we left school. A.not have written B. didn’t wrote C. haven’t wrote D. haven’t written 6 2. The word “………………..” which comes from Chinese means “big wind”. A. thunderstorm B. typhoon C. hurricane D. tornado 3. Hue will have temperatures ……………….200C and 250C A. between B. at C. with D. among 4. Minh doesn’t like listening to music on the way to school, ………………? A. did he B. doesn’t he C. does it D. does he 5. In many secondary schools in Vietnam, wearing school……………is compulsory. A. material B. cloth C. uniform D. color 6. They asked me ………………I lent them some money. A. if B. whether C. or D. A&B 7. The people ……………live next door keep having all night parties. A. which B. who C. whom D. whose 8. Tomatoes should ______ in the spring. A. plant B. be planting C. to be planted D. be planted 9. The librarian asked us ______ so much noise. A. don’t make B. to not make C. to make D. not to make 10. We feel _______ that all of you will get good marks in this test. A. hopeful B. bored C. sorry D. disappointed

A và B đều thuộc phân nhóm chính. A tác dụng với HCl giải phóng hidro. Số e lớp ngoài cùng của B bằng số phân lớp e của A. Số hiệu nguyên tử của A gấp 7 lần số hiệu nguyên tử của B. a) Xác định số hiệu nguyên tử của A và B. Viết cấu hình e của chúng. b) A và B có thể tạo được 2 hợp chất X và Y viết CTCT và giải thích liên kết trong X và Y. Nêu cách phân biệt X và Y

Cho anken X phản ứng với Brom ( trong dung dịch ) theo tí lệ mol 1:1, thu được chất hữu cơ Y ( chứa 74,08% Br về khối lượng ). Xác định CTPT của X?

Một đơn vị bộ đội có 10 người, ăn trong 10 ngày hết 100 kg gạo. Hỏi: a) Nếu đơn vị bộ đội đó có 20 người thì họ ăn trong bao nhiêu ngày hết 200 kg gạo? b) Nếu đơn vị bộ đội đó chỉ có 5 người thì họ ăn trong 20 ngày hết bao nhiêu kg gạo? (mức ăn của mỗi người giống nhau)

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Bac Lieu will have..... between 29°c and 34°c A) temperate B) weather C) temperatures D) sunny