笔者在近年来中考化学阅卷及平时教学中发现不少学生在根据化学方程式计算方面常出现错误,现归纳举例分析如下,以防患于未然.一、审题不认真,不明确反应原理或反应过程例1实验室用H_2还原mg CuO,加热一段时间后,冷却称得剩余固体的质量为ng,共用去wg H_2,求参加反应的CuO的质量. In recent years, the author has found that many students in the chemical examinations and usual teaching of the senior high school entrance examination have often made mistakes based on the calculation of chemical equations. They are now summarized and analyzed as examples to prevent problems. First, the question is not serious, and the reaction principle or reaction process is not clear. Example 1 The laboratory used H 2 to reduce mg CuO. After heating for a period of time, the mass of the remaining solid was cooled to ng, and the mass of CuO that participated in the reaction was calculated.