I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

What does this simple rebus mean?

What is the longest word in the dictionary?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

John was so frustrated to be the suspect of being a sleeper terrorist that he shoot himself right between the eyes with a revolver in his toilet. The revolver and the bullets were accurate. Minutes later John walks out of the toilet unharmed.
How can this be possible?

What breaks yet never falls, and what falls yet never breaks?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?