题目

Many people like to watch 3D movies. But do you know students in the US can watch 3D movies in class? They can learn a lot in 3D classes.In the US，some students can watch 3D movies in many classes，such as math，science and geometry（几何） classes. The 3D classes show a special(特别的) world to the students. They can help students understand the knowledge better. Students can remember the knowledge easily.The students like 3D classes very much. They say，“ It’s easy to learn，because you can remember all the things in the movies，and it’s fun to learn.”【1】The student（2009?普陀区二模）人类的生产活动离不开金属，下列三种金属被发现使用的先后顺序依次为：铜、铁、铝．（1）金属大规模被使用的先后顺序跟______有关①金属的导电性 ②地壳中金属元素的含量  ③金属的活动性（2）为探究金属Mg、Fe、Mn的活动性，在相同温度下，取大小相同、表面光亮的三种金属薄片分别投入等体积、等浓度的足量稀盐酸中（反应中Mn显+2价），请回答：金属MgFeMn反应现象放出气泡速率很快放出气泡速率很慢放出气泡速率较快结论三种金属的活动性：______＞______＞______（3）写出上述任一条反应方程式：______（4）除了用上述方法外，请你再设计一种方法证明三者的活动性：（药品自选，纯净的Mn是一种银灰色的金属）验证方法现象与结论