1. rancidification fixation of water is CHEMICAL CHANGE
2. Tearing of paper is PHYSICAL CHANGE
3. Rusting if iron is CHEMICAL CHANGE
4. Electrolysis of water is CHEMICAL CHANGE
This should not matter because the pipet has gradations and usually more of the sample is taken up in the pipette than what is delivered into the flask the student should always rinse the container being used because they are contaminating the sample if they do not clean it out
The study of chemistry helps us understand the nature of the world around us. Chemistry is always developing to keep up with any phenomenon that appears in nature.
Therefore, scientists and chemists are always developing new technologies. However, chemists must very careful when developing these new technologies. They should consider any bad chemical reactions that might occur and also chemicals that harmful to either the individuals or the environment.
