一、氧的性质和制法1.性质 O_2+2Mg■2MgOO_2+2Cu■2CuOO_2+4Na■2Na_2O初中学生学习化学方程式,死记呆背,不懂其实质的现象比较普遍。为改变这种状况,应尽可能地阐明化学反应的本质及其规律性。俗话说:打铁先得自己身子硬。为做到这一点,教师首先应懂得每个化学 First, the nature of oxygen and method of preparation 1. Properties O_2+2Mg ■ 2MgOO_2+2Cu ■ 2CuOO_2+4Na ■ 2Na_2O junior high school students to learn the chemical equation, remember to die, do not understand the essence of the phenomenon is more common. In order to change this situation, the nature and regularity of chemical reactions should be elucidated as much as possible. As the saying goes: Ironing gets its body hard. To do this, teachers should first understand each chemistry