[genericusername12345]

Hello Chemical Forums, I've got some homework for the finals and one of the topics that I could never understand is if there is any difference between the three states of matter and aqueous when they are next to a molecule and you have to predict the sign of the entropy change.
One of the exercises say: NaNO₃(s) NaNO₃(aq)
As you can see, there's no change in the molecule but the state of it (going from solid to aqueous), but other exercises say CH₄(g)+2O₂(g) CO₂(g)+2H₂O(l)

Am I overthinking all of this or is there an actual difference when trying to calculate the same molecules but different states of matter?

[Borek]

Definitely change of state means change in the entropy.

Imagine sublimating iodine, I₂(s) I₂(g) - which form has a higher entropy?