What does below chemistry rebus means?

John was piloting a plane behind a car but was never able to overtake it. Why?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

There was a minor accident with a doctor's son but the doctor noticed no major injury. After the treatment, the father of that doctors son is sitting with the son of the doctor without the doctor being in the room.

How can this be possible?

How many times in a given day, minutes and hour clock comes in a straight line ?

Can you find out the next digit in the following series ?

0, 0, 1, 3, 2, 6, 3, 9, 4, 12, 5, ?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

The captain of a ship was telling this interesting story: "We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly." How can that be possible?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?