Hãy tìm CTHH của khí A. Biết rằng: - Khí A nặng hơn khí hiđro là 17 lần. - Thành phần theo khối lượng của khí A là 5,88%H và 94,12%S.

Các câu hỏi liên quan

EXERCISE 3 I. Match the verbs in A with the phrases in B: A B 1. do a. swimming Answers: 1 + _____ 2. have b. pottery 2 + _____ 3. go c. a temperature 3 + _____ 4. make d. exercise 4 + _____ II. Choose the best answer by circling A, B, C or D: 1. I …………….. Nha Trang when I was a child. A. visit B. visited C. will visit D. have visited 2. He …………… to the USA so far. A. is B. was C. will be D. has been 3. Americans eat a lot of junk food, ………….junk food causes obesity. A. but B. and C. so D. because 4. Tim: I feel itchy and my nose is running. Doctor: ……………………….. A. Wash your hair more. B. I think you have the flu. C. Drink more water. Eat less meat D. I think you have a stomachache. 5. Pick out the word whose main stress is placed differently from the others. A. allergy B. headache C. temperature D. obesity 6. Choose the word that has the underlined part pronounced differently from the others. A. cold B. curly C. ocean D. clothes III. Choose the best answer to complete the passage: Headache is a very common disease. The symptoms (1)…….. a headache are various. People may (2)……….. pains only one side of the head. Sometimes when the pain goes away, the head is sore. People have a headache (3) …………. they work too hard or they are too nervous about something. (4)……….. can help cure the disease but people usually have to do more than taking tablets. They can prevent headaches by changing their diets or their (5)…………… or simply by going to bed. 1. A. on B. in C. of D. at 2. A. be B. have C. happen D. take 3. A. when B. but C. so D. and 4. A. Medicine B. Doctor C. Sport D. Fruit 5. A. life B. lifestyles C. hobbies D. working IV. Read the passage and complete the list of 5 volunteer activities in the passage: Ho Chi Minh Young Pioneer Organization is planning to help the community by encouraging you to participate in a recycling program. All you have to do is to collect used glass and cans, and send them for recycling. You can also donate old books to poor students in the city. By doing this, we can help save natural resources and earn some money for the organization. If possible, you can participate in other programs such as donating money to people in a flooded area, helping street children, giving away school uniforms to poor students and cleaning up the school yard. We hope you will join our programs. These are ways to change the world. 0. collect used glass and cans. 1. …………………………………………………………………………………………………. 2. …………………………………………………………………………………………………. 3………………………………………………………………………………………………….. 4. ………………………………………………………………………………………………… 5. ………………………………………………………………………………………………… V.Complete each sentence so it means the same as the sentence above. 1. I didn’t go to school because I was sick. -> I was sick, so ……………………………………………………………………. 2.It will be good if you eat less meat and more vegetables. -> You should ……………………………………………………………………… 3. He likes playing computer games in his free time. ->His hobby is …………………………………………………………………….. 4. I am interested in watching TV in the evening. -> I enjoy …………………………………………………………………………… 5.I think that learning English is important. ->I find …………………………………………………………………………….. III. Complete these sentences using the provided words: 1. My hobby / collect glass bottles. …………………………………………………………………………………… 2. I / start / my hobby / when / twelve / years old. ……………………………………………………………………………………. I often / share / my hobby / my mother. …………………………………………………………………………………….. I / feel / happy / when / look at / beautiful flower vases made from them. …………………………………………………………………………………….. I / continue / my hobby / future / because / it / help save the environment. ……………………………………………………………………………………