题目

(追加200分)帮忙修改语法问题
The concept of this lab was to validate the law of conservation of mass by using copper and sulfur. It was a chemical compound and both of them are synthetic materials that we used to observe the changes between the beginning and the consequences of the end of the experiment. The properties of these two pure elements copper and sulfur were ready to combine and to form a compound of copper sulfide. The major observations of this lab were that we wanted to know the chemical and physical reactions and the states of matter which were the transformation and the changes in appearance of a substance. For example, using the chemical substance, it always happens in a molecule level. Copper and sulfur, we were looking for the changes in mass, smelling differences, color changing, and among others; these are some instances of chemical reactions. I was forced on the physical changes; the shape of the substance and the color appearances had changed into next level which was the

提问时间：2021-03-06

答案

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