Answer:
kc = 20
Explanation:
The reaction is:
2SO₂ + O₂ ⇄ 2SO₃
Where kc is defined as:
kc = SO₃² / O₂×SO₂² (1)
The initial moles are 0,40 for SO₂ and 0,60 moles for O₂
The moles in equilibrium must be:
SO₂: 0,40 - 2x
O₂: 0,60 - x
SO₃: 2x = 0,30; x = 0,15
Replacing:
SO₂: 0,40 - 2×0,15 = 0,10 moles
O₂: 0,60 - 0,15 = 0,45 moles
Replacing these values in (1):
kc = 0,30² / 0,45×0,10²
kc = 20
I hope it helps!