设NA为阿伏加德罗常数的值.下列说法中,正确的是( )
A:标准状况下,22.4L的NO2和CO2混合气体中含有的氧原子数为4NA
B:密闭容器中,46gNO2和N2O4的混合气体所含分子个数为NA
C:常温常压下,22.4L的液态水含有2.24×10﹣8NA个OH﹣
D:高温下,16.8 g Fe与足量水蒸气完全反应失去0.8NA个电子
请和你的同学一起讨论讨论,找出答案。
Tom, Sam, Jim and Jack live in a building of four floors. They live on different floors. They have different jobs―an engineer, a worker, a teacher and a doctor. Tom lives above Sam, but below(在下面) Jim. Jack lives on the third floor. The doctor lives above the teacher, but below the worker. The engineer lives on the ground floor. What are their jobs? Which floor does each of them live on?
李叔叔有一辆自行车,李叔叔比自行车高____ 分米。
爱迪生小的时候,看见母鸡孵出了小鸡,心里很奇怪,心想:母鸡怎么能够孵出小鸡呢?于是。他把鸡蛋揣在怀里,甚至像母鸡那样蹲在鸡窝里,企图孵出小鸡。正是这样的好奇心和兴趣,爱迪生才成为了伟大的发明家。这启示我们( )
①好奇心可以刺激我们去不断探索未知世界的奥秘 ②只要有好奇心,就能取得事业上的成功
③好奇心可以造福社会,也可能把我们引上歧途 ④好奇心是学习、科研不断进步的动力
已知函数f(x)=(sinx+3cosx)2﹣2.
(1)当x∈0,π2时,求函数f(x)的单调递增区间;
(2)若x∈﹣π6,π3,求函数g(x)=12f2(x)﹣f(x+π4)﹣1的值域.