A:标准状况下,5.6L氯气和16.8L氧气的混合气体中含有分子数为NA
B:标准状况下,22.4LH2O所含有原子数为3NA
C:NA个N2分子所占的体积与0.5 NA个H2分子所占的体积比一定是2:1
D:1 molNa2O2与H2O完全反应,转移2NA个电子
________number of students went to visit that school last Sunday.
函数y= {x2(x<0)2x−1(x≥0) 的图象大致是( )