Question

what is 2.5 moles of oxygen

Answer 1

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.

Answer 2

Answer

Find the mass of 2.5 mole of oxygen atom . =8g.