题目

标准状况下VLNH3含有a个原子，则阿伏加德罗常数是( )A. 5.6a/V mol－1 B. 22.4a/V mol－1 C. 22.4a mol－ D. 11.2 a/v mol－1 答案：【答案】A【解析】根据公式：n=V/Vm计算出NH3的物质的量，再根据n=N/NA计算出阿伏加德罗常数。标准状况下VLNH3的物质的量为V/22.4mol，含有的原子总数的关系：（V/22.4）×4×NA=a，所以NA= 5.6a/V mol－1 ，A正确；综上所述，本题选A。Writing94. Write a composition in at least 60 words according to the given situation (根据所给情景写一篇 不少于60词的短文）April 23 is World Reading Day. Write a short passage of at least 60 words to call on your classmates to get into good habits of reading and read more good books. (4 月 23 日是世界读书 日，请写一篇短文，呼吁全班同学以实际行动迎接“世界读书日”的到来，为创建“书香校 园”，多读书，读好书，养成课外读书的好习惯。字数不少于60字，标点符号不占格。） Use the following points as a guide (短文须包含以下要点）1. What do the students who are not interested in study usually do in their spare time?2. What are the advantages of reading?3. What are your suggestions? Let’s read together As World Reading Day is coming, I'd like to recommend you to take up reading as a good habit for it's, in my eyes, a must for our teenagers. First, it's definitely the best way ...