What does below chemistry rebus means?

What is the relationship between these matchstick pictures below?

There were five men at church, and it started raining while they were outside. The four that ran still got wet, but the one that was still stayed completely dry. Why did he stay dry?

What you cannot hold but it is yours?

A thief is convicted in Mexico. He gets the death penalty. The judge allows him to say the last sentence to determine how the penalty will be carried out. If the thief lies, he will be hanged, if he speaks the truth he will be beheaded. The thief tells the last sentence and to everybody's surprise some minutes later he is set free because the judge cannot determine his penalty. What did the thief say?

Distances from you to certain cities are written below.

BERLIN 200 miles

PARIS 300 miles

ROME 400 milesAMSTERDAM 300 miles

CARDIFF ??? miles

How far should it be to Cardiff ?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

What word is pronounced the same if you take away four of its five letters?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

Can you solve the below tricky visual equation?