体液中Ca²⁺含量太低时，神经、肌肉的兴奋性升高而出现抽搐。这一事实说明Ca²⁺的作用之一是

   Mr. Smith is an English teacher. He comes from America. He has a daughter. Her name is Amy, and she is a good engineer in New York. Mr. Smith likes traveling very much, and he can speak Spanish very well. Now, he is in China, so he wants to learn some Chinese. He works very hard at his Chinese, and goes to Chinese classes every evening. He has a lot of friends in China and they often help him. He likes to talk with them. He tells his daughter that he can speak good Chinese, and he doesn’t have any trouble（麻烦） with his Chinese, but the Chinese have a lot.

下列不属于中东地区的焦点问题的是（  ）

下图为农夫山泉矿泉水瓶上的部分说明文字，列出了该饮用天然水理化指标．这里的钙、镁、钾、钠是指（　　）

现有下列十种物质：①液态氯化氢②小苏打 ③固体纯碱 ④二氧化碳⑤葡萄糖 ⑥氢氧化钾 ⑦氢氧化铁胶体 ⑧氨水 ⑨空气 ⑩硫酸铁溶液

（1）上述十种物质中，属于电解质的有____ ，属于非电解质的有____ ．

（2）有两种物质在水溶液中可发生反应，离子方程式为：H⁺+OH^﹣=H₂O，该反应的化学方程式为____ ．

（3）除去③中少量②的操作是____ ，化学方程式为　____ ．

（4）标准状况下，____ 　L ④中含有0.4mol 氧原子．

（5）现有100mL⑩溶液中含Fe³⁺5.6g，则溶液中SO₄^2﹣的物质的量浓度是____ ．

（6）若在⑦中缓慢加入⑥，产生的现象是____ ．

（7）将①加入到⑧中，⑧的导电能力变化为____ （填“增强”、“减弱”或“基本不变”）．