The following reaction plays a key role in the destruction of ozone In the atmosphere:

Cl (g) + O3 (g) - -> ClO (g) + O2 (g)

Given that S degree for CIO is 218.9J / (mol. K), use standard molar entropies (S degree) to calculate the delta S for this reaction.

19.91 J/K

Explanation:

The entropy is a measure of the randomness of the system, and it intends to increase in nature, thus for a spontaneous reaction ΔS > 0.

The entropy variation can be found by:

ΔS = ∑n*S° products - ∑n*S° reactants

Where n is the coefficient of the substance. The value of S° (standard molar entropy) can be found at a thermodynamic table.

S°, Cl (g) = 165.20 J/mol. K

S°, O3 (g) = 238.93 J/mol. K

S°, O2 (g) = 205.138 J/mol. K

So:

ΔS = (1*205.138 + 1*218.9) - (1*165.20 + 1*238.93)

ΔS = 19.91 J/K