设NA为阿伏加德罗常数的数值。下列说法错误的是()
A. 20g重水(D2O)中含有10NA个电子
B. 标准状况下,22.4L一氯甲烷的分子数约为NA
C. 4.6 g Na在氧气中完全反应生成Na2O和Na2O2,转移电子数为0.2NA
D. 25℃时,1L pH = 14的Ba(OH)2溶液中,Ba2+ 数为NA 答案:【答案】
D
【解析】考查阿伏加德罗常数的有关计算。选项D中氢氧化钡的浓度是0.5mol/L,含有0.5mol钡离子,Ba2+ 数为0.5NA,选项D不正确,其余选项都是正确的,答案选D。
选择方框中的句子完成对话。
Mike:Hello! 1 Jack:Speaking. Mike:This is Mike. Hi, Jack. I have two tickets for a basketball match. 2 Jack:I’d love to. 3 Mike:Let’s make it two. Jack: 4 Mike:At my home. Jack:OK. 5 Mike:See you.
A. When shall we meet? B. See you then. C. Can I speak to Jack, please? D. Would you like to go with me? E. Where shall we meet?