Question

number of oxygen atom in 8 gm of ozone

Answer 1

Given that  

Amount of O3 = 8 g

Number of moles = amount in g/ molar mass

= 8 g / 48 g/ mole

= 0.167 mole O3

1 mole O3 = 3 mole O

So  

0.167 mole O3 *3 mole O /1 mole O3

= 0.5 Mole O  

We know that 1 mole of O = 6.022*10^23 atoms  

So number of O atoms in 8 g = 6.022*10^23 atoms / 1 mole  

*0.5  mole

Or 6.022*10^23 /2 atoms  

The correct answer is 2)