A:金属钠与水反应:Na+ 2H2O = Na++ 2OH-+ H2↑
B:Ag2S沉淀溶解电离方程式:Ag2S(S)2Ag+(aq)+ S2-(aq)
C:Fe3O4与稀硝酸溶液反应: Fe3O4 +8H+ =2Fe3++ Fe2+ +4H2O
D:NaHCO3溶液与足量Ba(OH)2溶液混合:2HCO3-+Ba2++2OH- = BaCO3↓+2H2O+CO32-
同学们,本学期你们学了Water这个单元,请以“Water”为题,围绕以下问题用英语介绍以下水的来源,用途等方面的情况。40词左右。
Questions: 1. Where does water come from?
2. How do people use water?
Work bank: pond, tap, river, rain, lake, sea……
brush teeth, clean the floor, grow crops, put out fires, cook food……
Water is useful
Water is around us. ……
Water is useful. We must save water.
He____ find his____.
单词拼写(根据中文提示拼写单词)。