to find moles from any number of atoms, always divide by the constant called Avogadro's Number. This number is representative of the number of atoms or molecules in a mole of any substance and is equal to about [tex]6.022* 10^{23}
[/tex].
So, for this problem, we take the number of atoms of oxygen and divide by Avogadro's Number.
[tex] \frac{3.98* 10^{23} O_{2} atoms }{6.022* 10^{23} atoms/mol } = 0.6609 moles[/tex]
Answer: 0.661 moles (after rounding)
Make sense?
