Đốt cháy 20,16 gam sắt trong bình chứa 4,48 lít khí oxi (ở ĐKTC) sau phản ứng thu được sắt từ oxit A.viết phương trình phản ứng xảy ra B. Sau phản ứng chất nào còn dư? Dư bao nhiêu gam?

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IV Read the passage and answer the questions.(1.0 point) Visual pollution has a greater effect on people than you may think. I remember when I went to a big city, I was really scared because so much graffiti on the buildings' wall. Then I looked up, and I saw a lot of power lines over my head. Although they were not dangerous, I still felt unsafe since I thought they might fall down. These things prevented me from enjoying the beautiful sights of the city. I also remember the time when I was a student at a university. Once I was so busy with my assignments that I did not tidy my room for two weeks. Looking at the messy room caused me so much stress that I did not want to study. Then I decided to clean the room and put my thing in their proper places. I also bought a small plants and placed it in a corner of the room. These simple actions increased my motivation and helped me to focus on my learning. Questions. 1.How did the author feel when she saw the power lines? …………………………………………………………………………………………………. 2.Why did she have that feeling? …………………………………………………………………………………………………… 3. What was she busy with? …………………………………………………………………………………………………… 4. What happened when she looked the messy room? …………………………………………………………………………………………………… V. Choose the correct answer for each gap to complete the following passage. Rivers are ____(1) ____ of the world’s most important natural resources. Many cities are on large rivers, and____ (2)____ every country has at least one river that ___(3)___ an important part in the lives of its people. Besides transportation, rivers ___(4)___ food, water for crops, water to drink, and opportunities for recreation for people who live along their ____(5)____. And in order to get water for crops, engineers sometimes build a dam (đập, đê) across a river and let the water become a lake ____(6)____ the dam. Then people can use their water not only to ___(7)___ fields but also to make electricity for homes and industries. ____(8)___, the water often becomes polluted when cities on river banks grow ____(9)____ size and the number of industries increases. We are learning that it is necessary to ____(10)_____ rivers clean if we want to enjoy the benefits of the natural resources. 1. A. one B. ones C. among D. those 2. A. most B. mostly C. almost D. about 3. A. takes B. makes C. occupies D. plays 4. A. supply B. provide C. distribute D. bring 5. A. banks B. shores C. sides D. beaches 6. A. behind B. on C. below D. under 7. A. take B. irrigate C. drain D. give 8. A. Moreover B. Therefore C. Thus D. However 9. A. of B. about C. in D. for 10. A. keep B. get C. hold D. maintain

1/ Đặt tính rồi tính: 320 x 250 483 x 253 23520 : 56 123220 : 714 …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. 2/ Điền số hoặc kết quả thích hợp vào chỗ chấm: a/ 24000kg =……………..tấn b/ 3giờ 5phút =…………………..phút c/ 14 km2450m2 = =………….....m2 d/ 8004200m2=…………....km2…….…….m2 e/ Một thửa ruộng hình bình hành có đáy 45m và chiều cao 28m. Vậy diện tích thửa ruộng đó là ………….. 3/ Viết thương của các phép chia sau dưới dạng phân số rồi đọc phân số: a/ 12 : 7 viết là …………. ; đọc là ………….………….………….………….…………. b/ 25 : 13 viết là …………. ; đọc là ………….………….………….………….…………. c/ 34 : 57 viết là …………. ; đọc là ………….………….………….………….…………. 4/ Tìm Y: Y : 11 = 78 Y 90 = 37800 …………………………………………………………………………………………………. …………………………………………………………………………………………………. 5/ Một sân chơi hình chữ nhật có chiều dài 65m, chiều rộng 40m. Hỏi cần bao nhiêu viên gạch hình vuông có cạnh 50cm để lát kín san chơi đó (biết diện tích phần mạch vữa không đáng kể) …………………………………………………………………………………………………. …………………………………………………………………………………………………. …………………………………………………………………………………………………. (Ai xài điện thoại viết bài chia ra giấy rồi chụp giúp em!)