using the data from the following table:
Substance ΔH∘f (kJ/mol) ΔG∘f (kJ/mol) S∘ [J/(K⋅mol)]
Na(s) 0.00 0.00 51.30
Cl2(g) 0.00 0.00 223.1
NaCl(s) -411.0 -384.0 72.10
Express your answer to four significant figures and include the appropriate units.
Standard Entropy Table
So what you do is ΔS∘=S∘(products)−S∘(reactants)
so you take the product and multiple it by the coefficient. You do the same to the product. So it becomes.
2 x 72.10- (2x 51.30 + 233.1)
= -181.5 J/K
Hope this helps!