A nuclear-decay particle with a mass of O amu and a charge of -1 is known as

if you're asking what comes out, it's steam.

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.