Which of the following is a physical change? a. corrosion b. explosion c. evaporation d. food spoilage

C. evaporation

Explanation:

A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.

Example: evaporation  as it involves change of state from liquid to gas

A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.

Example: Corrosion as it leads to formation of new substances.

Explosion as it leads to release of heat.

Food spoilage as it involves chemical combination with oxygen.

Thus evaporation is a physical change.

yes yes yes yes yes yes yes yes yes yes yes yes yes yes yes

explanation:

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.