3. Identify each of the following observations as evidence of either a physical change or a chemical change.
(a) A piece of copper is heated until it melts.
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(b) A piece of aluminum corrodes in a solution of acid.​

Esign techniques and materials that reduce the negative environmental impact of a structure are referred to as

The conventional equilibrium constant expression (kc) for the system below is: 2icl(s) ⇄ i2(s) + cl2(g) [cl2] ([i2] + [cl2])/2[icl] [i2][cl2]/[icl]2 none of the listed answers are correct [i2][cl2]/2[icl]

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.