Expire Worthless is when options enter expiration out of the money and expire without any remaining value. Expiring worthless is one of the most common terms used in options trading. Options expire worthless whenever they go into expiration out of the money.
A single molecule of water consists of three atoms. H2O is built from a single atom of oxygen that is single-bonded with two atoms of hydrogen.
Avogadro's number tells us there are 6.022 x 1023 molecules of water per mole of water. So, next we calculate how many molecules there are in a drop of water, which we determined contains 0.002775 moles: molecules in a drop of water = (6.022 x 1023 molecules/mole) x 0.002275 moles.