A:20°
B:40°
C:70°
D:110°
下列河流中汛期最长的是
等质量的氮气和氧气中,所含分子数较少的是____
6 C
12.01
7 N
氮
14.01
8 O
氧
16.00
____ ____he has been so ____ ____ us, I ____ ____we have to punish him or he won't respect us.
①SiO2﹣→Na2SiO3;②CuSO4﹣→CuCl2;③SiO2﹣→H2SiO3 ;④CuO﹣→Cu(OH)2;⑤Na2O2﹣→NaOH.