Question

calculate mass of
2.5 mole of oxygen molecule​

Answer 1

1 g atom of oxygen = 16 g (which is equal to 1 mole) similarly 1 g molecule of oxygen = 32 g (O 2) (which is also equal to 1 mole of O 2 molecule) hence 2.5 g atom of oxygen = 2.5 x 16 = 40g.

Answer 2

Number of moles = Mass / Atomic mass

• ° • Mass = Number of moles × Atomic mass

= 0.5 × 16

= 8 g