What does below chemistry rebus means?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

An office is divided into 8 cubicles. How many of the cubicles are painted if only 1/8 of the cubicles are painted?

In the four images below, can you find the odd one out?

What does below Rebus mean ?

esgg sgeg gegs gsge

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

John is looking at Jenifer, but Jenifer is looking at Jacob. John is married, but Jacob is not.

Is a married person looking at an unmarried person ?

Can you find out the remainder when 3^300 is divided by 5?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?