In the following list, only is not an example of a chemical reaction.

a) burning a plastic water bottle

b) the production of hydrogen gas from water

c) the tarnishing of a copper penny

d) chopping a log into sawdust

e) charging a cellular phone

Thus chopping a log into sawdust is not an example of a chemical reaction.

Explanation:

Physical reaction is a reaction in which there is no rearrangement of atoms and thus no new substance is formed. There is only change in physical state of the substance.

Example: chopping a log into sawdust as the shape and size of wood changes.

Chemical reaction is a reaction in which there is rearrangement of atoms and thus new substance is formed. There may or may not be a change in physical state.

Example: burning a plastic water bottle : as the plastic would combine with oxygen to give oxidised products.

the production of hydrogen gas from water: the chemical composition changes

the tarnishing of a copper penny: oxidation of copper takes place to give copper oxide.

charging a cellular phone: the electrical energy is used for a chemical reaction

3

explanation:

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )