47里面有[ ]
A.4个十7个一
B.7个十4个一
答案:A
—What's his name?
—____________.[ ]
A. Her name is Kim.
B. His name is Jim.
C. My name is Li Ming.
设阿伏加德罗常数的数值为NA,下列说法正确的是 ( )
A.1mol Cl2与足量的铝反应,转移电子数为3NA
B.1.8g H2O中含有的电子数为 NA
C.标准状况下,22.4L Cl2与HCl的混合气体中分子总数为2 NA
D.在1 L 0.1 mol/L醋酸钠溶液中,CH3COO-离子总数为0.1NA