Several substances in the kitchen are talking to each other, and you think of them as physically cha

A. In the process of breaking the glass, there is no new substance, but the shape of the glass has changed, which is a physical change;

B. In the process of gas combustion, there are new substances such as carbon dioxide, which are chemical changes;

C. In the process of kitchen knife rusting, there is the formation of new substance rust, which is a chemical change;

D. In the process of food decay, new substances are generated, which is a chemical change. Therefore, I chose the A test point: the identification of chemical changes and physical changes.

Comments: This question is not very difficult, and the answer should be analyzed whether there is a new substance formed in the process of change, if there is no new substance, it is a physical change, and if there is a new substance, it is a chemical change.

Several substances in the kitchen are talking to each other, and what you think is a physical change in their narrative is (A).

A glass: I was broken.

B Gas: I burned.

C Kitchen Knife: I'm rusty.

D Food: I'm rotten.

Analysis: A. In the process of breaking the glass, there is no new substance, but the shape of the glass has changed, which is a physical change;

B. In the process of gas combustion, there are new substances such as carbon dioxide, which are chemical changes;

C. In the process of kitchen knife rusting, there is the formation of new substance rust, which is a chemical change;

D. In the process of food decay, new substances are generated, which is a chemical change.