Which would show an example of how physical changes are reversible? a cutting a gold bar in two pieces and then putting the pieces next to each other b burning a match and then relighting it c melting tin and then cooling it into a mold d combining sodium and chlorine to make the new material of table salt

Option (C) is the correct answer.

Explanation:

A change in which there will be no formation of a new compound and in which there occurs no change in chemical composition is known as a physical change.

Also, a change in which reactants can be recovered from the products or vice versa is known as a reversible change.

For example, melting tin and then cooling it into a mold is a physical change as no new compound is forming. Also, it is a reversible change because by heating the tin we can melt is again.

Thus, we can conclude that melting tin and then cooling it into a mold show an example of how physical changes are reversible.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

answer; talc and gypsum;