Question

How many moles of oxygen (O) atoms are in a sample of 3.98 × 1023 atoms? 0.661 mol O 1.51 mol O 6.60 × 1022 mol O 2.40 × 1047 mol O

Answer 1

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
`6.022* 10^(23)`.

So, for this problem, we take the number of atoms of oxygen and divide by Avogadro's Number.


`(3.98* 10^(23) O_(2) atoms )/(6.022* 10^(23) atoms/mol ) = 0.6609 moles`

Answer: 0.661 moles (after rounding)

Make sense?