Do all chemical bonds involve the sharing of electrons between two atoms

What is the value of keq for the reaction expressed in scientific notation

Compare and contrast physical changes with chemical changes.

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.