What does below chemistry rebus means?

If a boy blows 18 bubbles,
Then pops 6 eats 7 and then
He pops 5 and blows 1.
How many are left?

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Bay of Bengal is in which state?

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?

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?