=Taro stated that when someone hits a golf ball with a club, the amount of energy the ball has changes, the amount of energy that the club has changes, and the total energy of the system that includes the ball and the club increases. Which best explains Taro’s error? The amount of energy that the ball has does not change.
The amount of energy that the club has does not change.
The total energy of the system remains the same.
The total energy of the system decreases.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

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.