Cho từ từ a mol CO2 vào dd chứa b mol Ca(OH)2. (b < a < 2b) ta thu được kết tủa. a) Tính khối lượng kết tủa theo a, b? b) Tính khối lượng muối tạo ra theo a, b?

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Part IV. Fill in the numbered blanks in the passage with ONE suitable word from the box. Write your answers on the answer sheet. There is TWO extra word. might However machines important Scientists use give pollution from find Energy is very (21) _________ in modern life. People use energy to run (22) _________, heat and cool their homes, cook, (23)_________light, transport people and products from place to place. Most energy nowadays comes from fossil fuels such as petroleum, coal and natural gas. (24) _________, burning fossil fuels causes (25) _________ . Also, if we don’t find new kinds of energy, we will (26). _________up all the fossil fuels in the twenty-first century. (27) _________ are working to (28) _________ other kinds of energy for future. What might these sources of energy be? Part V. Read the passage and choose the correct answer A, B, C or D for each of the following questions. Write your answers on the answer sheet. A lot of children are picky eaters. For example, they don't like meat, they don’t want any vegetables, and they only want ice cream. Some people never change. Mary is a good example. She’s an adult now, but she’s still a picky eater. She says, “I only eat foods I like.” Mary loves fruit, and she eats some fruit every day, but she doesn’t eat any vegetables. “Don’t even show me lettuce or carrots!” she says. What does she like? “Pizza is my favorite food. I eat pizza at least five times a week. I have it with green peppers and onions, so I eat some vegetables!” What are her other favorite foods? She likes chocolate. She usually has some chocolate several times during the day. Does Mary plan to change her eating habits? “Not if I have a choice,” she says. “So don’t offer me any salad, OK?” 29. The best title of the passage is _________ A. Children's food. B. Picky eaters. C. Children's eating habits D. Children's favorite foods 30. According to the passage, Mary dislikes _________most. A. pizza B. vegetables C. fruit D. meat 31. Which of the following sentences is NOT correct? A. Mary only eats the food she likes. B. Mary doesn’t like vegetables. C. Mary plans to change her eating habits. D. Mary likes fruits, chocolate and pizza. 32. How does Mary feel about salad? A. She likes salad. B. She doesn't like salad. C. She loves salad. D. She thinks it's great. 33. Picky eaters are the people who _________ A. don't like meat B. don't want any vegetables C. only like ice cream D. only eat the foods they like Part VI. Rewrite each of the following sentences in such a way that it means exactly the same as the provided sentence. Write your answers on the answer sheet. 34. If someone doesn’t put the coal in, the fire will go out. -> Unless _____________________________________________________________. 35. She started working as a secretary five years ago -> She has _____________________________________________________________. 36. The storm destroyed many houses in this village last week. -> Many houses _____________________________________________________________.