Answer:
Mass = 192 g 
Step-by-step explanation:
Given data:
Moles of SO₂ = 6 mol
Mass of oxygen needed = ?
Solution:
Chemical equation;
S + O₂ → SO₂
Atomic ratio:  
 SO₂ : O₂ 
 1 : 1
 6 : 6 
Mass of oxygen:
Mass = number of moles × molar mass
Mass = 6 mol× 32 g/mol
Mass = 192 g