J.R. is this correct?

Question

Calculate the value of the standard molar entropy S°, for B₂ (g) at 25°C

Substance: AB (g) Standard Molar Entropy, S° (J/Kmol): 217.9

substance: AB₂ (g) Standard Molar Entropy, S° (J/Kmol): 238.1

is the answer 238?

Answer 1

Don't know for sure because we don't know the standard states of the different elements/compounds. I thought this might be a Hess' law problem, but don't think we can do that without additional information. If you explain how you arrived at 238 kJ/mol, maybe I'd better understand the approach and could better judge if the answer is correct or not. Sorry I can't be of more help at this time.