Đáp án:
Giải thích các bước giải:
Na2CO3+H2SO4->Na2SO4+CO2+H2O
2NaHCO3+H2SO4->Na2SO4+2CO2+2H2O
nCO2=2,016/22,4=0,09 mol
gọi a là nNa2CO3 b là nNaHCO3
ta có
106a+84b=1,9
a+b=0,09
Giải ra nghiệm âm
Bạn xem lại đề nhé
Giúp mình với mọi người ơi hứa vote 5 sao 20. As tourism is more developed, people worry about the damage to the flora and faunaof the island. A. fruits and vegetables B. plants and animals C. flowers and trees D. mountains and forests Mark the letter to indicate the word(s) OPPOSITE in meaning to the underlined word(s). 21. Their classmates are writing letters of acceptance. A. confirmation B. agreement C. refusal D. admission 22. We offer a speedy and secureservice of transferring money in less than 24 hours.. A. uninterested B. unsure C. open D. slow Read the passage and choose the best answer. There is now increasing concern about the world’s energy (23)____ , particularly about those involving fossil (24) ____. In less than a hundred years we shall probably exhaust all the present (25) ____ of oil and gas. The world’s coal (26) ____ should last langer but, once used, these cannot be renewed. It is important; therefore, that we should develop such (27) ____ sources of energy as solar energy as well as water and wind power. 23. A. possessions B. resources C. goods D. materials 24. A. fuels B. powers C. forms D. energies 25. A. findings B. productions C. numbers D. sources 26. A. reserves B. stores C. mines D. contents 27. A. traditional B. alternative C. revolutionary D. surprising Read the passage and choose the best answer. An artist went to a beautiful part of a country for a holiday and stayed with a farmer. Everyday he went out with his paints and his brushes and painted from morning to evening, and then when it got dark, he went back to the farm and had a good dinner before going to bed. At the end of his holiday he wanted to pay the farmer, but the farmer said: "No, I do not want money, but give me one of your pictures. What is money? In a week it will all be finished, but your painting will be still here." The artist was very pleased and thanked the farmer for saying such kind of things. The farmer still smiled and answer "It is not that. I have a son in London. He wants to become an artist. When he comes here next month, I will show him your picture, and then he will not want to become an artist any more. I think." 28. Where did the artist spend his holiday? A. In a beautiful country. B. On a farm. C. With a farmer. D. With his paints and brushes. 29. What did the farmer go out for? A. He went out for his holiday. B. He wanted to have sleep outdoor. C. He went out for his paintings D. He preferred to have dinner in the open air 30. What did the farmer ask the artist t the end? A. He asked for money. B. He asked for his wages. C. He asks for a picture. D. He asked the artist to teach him to be an artist . 31. Why was the artist pleased with the farmer's request? A. Because he thought his pictures were so beautiful. B. Because he had so many kind of paintings C. Because he would sell one of his pictures. D. Because the farmer had thanked him. 32. The farmer's son wouldn't want to become an artist any more........................... A. because he lived in London. B. because he had the artist's painting. C. because he had seen the artist's painting. D. when he come here. II. WRITING (2pts) Finish the second sentences so that it has a similar meaning to the first one. 33. My father stopped smoking two years ago. ->My father hasn’t…...……………………………………………………………………… 34. It is useful to get access to the Internet. ->Getting……..…………………………………………………………………………… 35. Wine is bad for us, so are cigarettes. ->Both……………………………………………………………………………… 36. Mount Everest is higher than any other mountains in the world. ->Mount Everest is………………………………………………………………….…….. Combine two sentences into a new one by using the given words in the brackets. 37. Staying at home is better than going out in this wet weather. (Rather) ………………………………………………………………………………………………… 38. If some one doesn’t put the coal in, the fire will go out. (Unless) ………………………………………………………………………………………………… 39. The furniture was so expensive that I didn’t buy it. (Such…..that) ……………………………………………………………………………………………… 40. They won’t buy the new car. They save enough money. (Until) ………………………………………………………………………………………………
giúp em làm bài 5 em hứa vote 5 sao
Hãy sáng tác 1 bài thơ ( theo thể thơ lục bát) nói về việc phòng chống dịch covid-19
Hãy sang tác 1 bài thơ thơ lục bát nói về cách phòng chống dich covid -19
II. Put the following sentences in question tags: 1. Tom won’t be late,……………………..? 2. You’re tired, …………………..............? 3. You haven’t lived here long,………..….? 4. You’ve got a camera, …………..……...? 5. There aren’t many people here yet,.…...? 6. Sue doesn’t know Ann,……………..….? 7. You came in airport car,………….……? 8. These cakes look good,………………..? 9. You can speak German,…………….…? 10. I’m too impatient,……………….…….? 11. Jack is on holiday, ……………………? 12. You couldn’t do me a favor, ….……..? 13. Peter plays soccer very well, .......................................................... ? 14. You don’t like coffee, .............................................. ? 15. Her father goes to work at 6 AM, ........................... ? 16. This picture is yours, .................................... ? 17. They won’t go to HCM City next week, .............................. ? 18. My parents have used the internet very often, ............................. ? 19. Your house isn’t very far from school, ............................ ? 20. Hoa never comes to school late, .......................................... ? 21. You took some photos on the beach, ............................... ? 22. We must communicate with you by means of e-mail or chatting, ..................... ?
Giúp mình 2-3 câu ngắn bất kỳ vs. Thanks nhé
Giúp mình vs Đỉnh cao của cách mạng tháng 8 được đánh dấu bằng sự kiện nào? Tại sao?
vẽ tam giác abc vuông tại a biết ab nhỏ hơn ac. Giúp em với
Viết đoạn văn về vấn đề đọc sách hiện nay của học sinh (chú ý có sử dụng các thành phần biện lập.Gạch chân thành phần biện lập đó)
Các bạn vẽ đẹp ơi vẽ giúp mình nhân vật Zenitsu mình cảm ơn tô màu hay không tô cũng được ạ!!
Loga.vn - Cộng Đồng Luyện Thi Trực Tuyến