2Cl(g) ⇌ Cl2(g)

Calculate the ΔH, ΔS and ΔSuniverse for this reaction.

Determine the spontaneity of the reaction.

-121.301 kJ·mol⁻¹;  57.8 J·K⁻¹mol⁻¹; 464.9 J·K⁻¹mol⁻¹; spontaneous

Explanation:

                         2Cl(g) ⇌ Cl₂(g)

ΔHf°/kJ·mol⁻¹:  121.301       0

S°/J·K⁻¹mol⁻¹:  165.190   223.0

1. ΔᵣH

ΔᵣH = products -reactants = 0 - 121.301 = -121.301 kJ·mol⁻¹

2. ΔᵣS

ΔᵣS = products - reactants = 223.0 - 165.190 = 57.8 J·K⁻¹mol⁻¹

3. ΔS(univ)

4. Spontaneity

ΔG is negative, so the reaction is spontaneous.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"