How many molecules are in 2.50 moles of O2

There are 6.022×1023 O2 molecules in a mole of O2. Since you have 2 oxygen atoms in one O2 molecule, there are 2×6.022×1023 O atoms in a mole of O2.

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.