9.37 entropy change [ENDORSED]

[Cam Bear 2F]

For letter d, find the standard reaction enthalpy for the decomposition of potassium chlorate 4KClO3(s) -> 3KClO4(s) + KCl(s) and interpret the sign and magnitude of the reaction entropy, the solutions manual says that the four moles of solid products are more ordered than the four moles of solid reactants and that's why the entropy change is negative. Can someone please explain how you can tell which is more ordered?

[Chem_Mod]

Draw the Lewis structure for ClO₃^- and ClO₄^-.
Both have 4 regions of electron density around the Cl atom.

But ClO₃^- has a lone pair and that lone pair can be in one of 4 locations (and therefore higher number of possible states/entropy).

Go through this in one of the peer learning sessions or in study group.