碱金属的化学性质:钾的保存及取用方法: (1) 与氧气反应差异性:(将横线补充完整)Li+O2 ( 色、氧化锂); Na+O2 ( 色、过氧化钠); K+O2 ( 色,); Rb+ O2 (棕色、); CS+ O2 ( 色、 ). (2) 与水反应差异性:(填反应现象)2Li+2H2O=2LiOH+H2↑( );2Na+2H2O=2NaOH+H2↑(剧烈);2K+2H2O=2KOH+H2↑( );2Rb+2H2O=2RbOH+H2↑(更猛烈、燃烧、爆炸). (3) 写出下列反应的化学方程式:过氧化钾与CO2: ;超氧化钾与水、CO2: 、 ;氧_____ of danger in the street at night, she had to go
home with a friend _____ her.
A.Being warned;
accompanied B.Having
warned; accompanying
C.Warning;
accompanying D.Having been
warned; accompanying