题目

— When will the bike-sharing schemes be introduced to the public? — Not until a better understanding of them. A . will we have had B . have we had C . we will have had D . we have had 答案:D请根据所提供的试剂和仪器,按要求填空: (1)写出带有标号①的仪器的名称___________ (2)若用气体发生装置A来制取O2(使用MnO2作催化剂的情况),其反应的化学方程式为:                                    (请标出电子转移方向与数目);若用气体发生装置B来制取O23.36L(标准状况),转移电子的数目是        。选择的收集装置是__      __(填序号)。
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