题目

设NA为阿伏加德罗常数的值，下列叙述正确的是( )A.标准状况下，22.4L H2O含有分子数为NAB.分子总数为NA的N2、CO混合气体体积约为22.4L，质量为28gC.常温常压下，1.6g CH4含原子数为0.5NAD.0.2mol/L K2SO4溶液中有0.4NA个K+ 答案：【答案】C【解析】A. 标况下，水不是气体，不能使用标况下的气体摩尔体积计算22.4L水的物质的量，故A错误；B. 分子总数为NA的N2、CO混合气体的物质的量为1mol，由于没有告诉在标况下，不能使用标况下的气体摩尔体积计算1mol混合气体的体积，故B错误；C. 1.6g甲烷的物质的量为0.1mol，0.1mol甲烷分子中含情景选择。根据对话情景，从每题所给的三个选项（A、B和C）中，选出最佳选项。小题1: —I like reading interesting stories.— _________.A. I do like them                                   B. The same to you                             C. So do I小题2:—Can I park my car here, madam?— _________. There is much traffic here.A. Of course not                                   B. You’d better not                              C. Never mind小题3: —It is said the rain will last at least five days.—_________. There is too much rain in our areas these days. It may cause flood.A. I’m afraid not                                   B. I’m afraid so                                     C. I hope not 小题4:—Would you like to have dinner with us, Maria?—_________. Where shall we eat?A. Sorry, I’m busy                                 B. I’m afraid I can’t                    C. I’d love to小题5:—I’ll go to Shanghai for a visit during the summer holidays.—_________!A. Have a good trip                          B. Good idea                                   C. Well done