What are some ways you can determine a chemical change has occured

1. Color changes.

The Statue of Liberty, though known for its green color, was originally covered in a layer of copper. After a redox (reduction-oxidation reaction) the color changed due to a chemical change.

2. Gas Production

3. Light Produced

Light sticks work as the result of a chemical reaction between hydrogen peroxide and phenol oxalate ester.

4. Temperature Changes

5. Volume Change

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.