If you say my name, I will no longer exist. What am I?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

If eleven plus two equals one, what does nine plus five equal?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

The more you take me, the more you leave me behind.
Who Am I?

Before Mount Everest was discovered, what was the highest mountain in the world?

During which month do people sleep the least?

Seven Robbers robbed a bank and hide the coins in a lonely place.
They decide to divide the money equally the next morning. Two greedy robbers decided to cheat the others and reach the place at night. They equally divided the coins between them, one coin left. So they called another robber and then they decided to divide equally among the three. Sadly again one coin left. The same thing happened to the 4th 5th and the 6th robber.
However, when the 7th robber reached in the morning, they can divide the coins equally.

How many coins were there in total?

I know a nine-letter word having only one vowel.
Do you ?