Đáp án:
4Cu+O2 --->2Cu2O
2Fe+O2-->2FeO
4Na+O2-->2Na2O
2Mg+O2-->2MgO
4P+ 10 O2-->2P2O5
2S+3O2-->2SO3
2H2+O2-->2H2O
C+O2-->CO2
Giải thích các bước giải:
a, CuO: đồng oxit
FeO : sắt oxit
Na2O: natri oxit
MgO: magie oxit
b,P2O5: điphotpho penta oxit
SO2: lưu huỳnh đioxit
H2O: nước
CO2: cacbon đioxit
Một thửa ruộng hình thang có độ dài đáy lớn bằng chiều cao của mảnh đất hình tam giác có diện tích là 324m 2 và độ dài đáy là 18m. Đáy lớn của thửa ruộng gấp 3 lần đáy bé. Đáy bé dài hơn chiều cao 5m. Tính diện tích của thửa ruộng hình thang?
I. Combine these sentences, using relative pronouns. 1. Alice is my friend. Alice’s mother died last year. 2.The boy will be punished. He threw that stone. 3. Ann is very friendly. She lives next door. 4.The man is a famous actor. You met him at the party last night. 5.There are some words. They are very difficult to translate. 6.I was looking for a book this morning. I’ve found it now. 7.Is that the car? You want to buy it. 8.Sandra works in advertising. You were talking to her. 9.The little girl ate sweets the whole way. She sat next to me on the coach. 10.Lan is a journalist. Her tape recorder was stolen. 11.I don’t know the name of the woman. I spoke to her on the phone. 12. We often go to visit our friends in Bristol. It’s only 30 miles away. 13. This is Mr Carter. I was telling you about him. 14. That is the room. The meeting is held in that room. 15. I’ll always remember the day. I first saw that sight on that day. 16.She was born in Malaysia. Rubber trees grow well there. 17.No one knows the school. My uncle taught at that school 10 years ago. 18. Please ask them the time. The train stared the trip at that time. 19. New Year’s Day is a day. All family members gather and enjoy a family dinner then. 20. There are many hotels. Tourists can enjoy their holidays there. 21.India is a country.The earthquake occured in this country last month. 22. Bac giang is a city. I was born and grew up there. 23. We have not decided the day. We’ll go to London on that day. 24. The man made me sad the most. I love him with all my heart. 25.The thief was caught. This was a really good news. 26. The gentleman was very young. He was introduced as the most successful businessman. 27. His book became the best seller.It was punished last year. 28. Neil Armstrong lived in the USA. He walked on the moon. 29. Nam is very intelligent. He learns in our class. 30. Ha Long has grown into a big city over the past few years. I visited the city last year. II. Supply these verbs in correct tenses. (Chia động từ trong ngoặc). 1.She wishes her father ( be) here now to help her 2.I wish they ( visit) us when they were in town. 3.I wish someone ( give) me a job next month. 4.If only I ( can take) the trip to Hanoi with her next summer. 5.I wish they ( know) the truth yesterday. 6.I wish I (see) that film on TV again. 7.We wish she (be) our teacher of English. 8.My brother wishes he (not waste) time when he was young. 9.They wish they (come) to class on time yesterday morning. 10. I wish I ( spend) my last summer vacation in the mountains. 11.I wish she (come) to see me yesterday. 12.If only I ( have) more time to do this job. 13.He missed an exciting football match on TV last night. He wishes he ( watch ) it. 14.I wish you ( not give ) them my phone number yesterday. 15.We wish we ( understand) all the teacher’s explanation yesterday.
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Câu hỏi như sau: Hùng bán 200 con tem, trong đó có 3/5 số tem Hùng bán nửa giá. Số còn lại Hùng bán đúng giá là 8000 đồng/ con tem. Hỏi Hùng nán hết số kem được bao nhiêu tiền? HỨA AI LÀM ĐÚNG VOTE CHO 5 SAO VÀ CHỌN CÂU TL HAY NHẤT LUÔN NHÉ!!!
Exercise 7: Rewrite the sentences with "used to". 1. They often went to Da Lat in the summer. 2. We usually played soccer in the past. 3. I got up earlier when I had work. 4. Tom did his homework in the evening. 5. Lan wrote to Mary twice a month. 6. He worked at night when he worked in the supermarket. 7. Did they watch TV in the past? 8. She played badminton in her free time. 9. They went swimming in the afternoon in 1990. 10. He was a doctor in that hospital.
1. một ô tô có khối lượng 1 tấn đang chuyển động với vận tốc 54 km/h.động lượng ô tô 2.một vật có khối lượng 200 g đặt trên mặt bàn nằm ngang .hệ số ma sát trượt giữa vật và mặt bàn là 0,3 vật bắt đầu kéo bằng lực f=2N CÓ phương ngang g=10m/s2 quãng đường vật đi được sau 2s là?
giải thik câu sau: - Gió thổi là chổi trời
Mọi người giúp mình nhé, mình cần gấp
so sánh diện tích tự nhiên châu phi và châu mĩ
Dòng nào chỉ ra đúng nhất các biện pháp tu từ được sử dụng trong đoạn thơ: “Từ Triệu, Đinh, Lí, Trần bao đời xây nền độc lập/ Cùng Hán, Đường, Tống, Nguyên mỗi bên xưng đế một phương/ Tuy mạnh yếu từng lúc khác nhau/ Song hào kiệt đời nào cũng có.” 1 điểm A. So sánh B. Điệp ngữ C. Liệt kê D. Gồm ý A và C
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