Questions about Entropy changes.

In chemistry we recently did a lab session involving the reduction of ferricyanide to ferrocyanide. The change in entropy for this was calculated to be -151.0102452 J/mol. There are 2 question in my lab manual that I've been researching for a while now but cannot find any useful sites for.

1: Comment on the relatively large magnitude and sign of the change in entropy in the experiment (I know that the entropy change means there is more order being created but I'm not sure what else I could say about it)

2: The change in entropy for a Zn-Cu cell is -16 J/mol. Comment in why the change in entropy is relatively small (someone suggested it being due to no gas phase molecules being present in the reaction but that doesn't seem correct.)

Thanks for any help with this, it hasn't been very well explained so far in college.

quite difficult what you are seeing (dont know this myself), i can only say the following:
in literature (see sources 1 and 2) i found that
S0(ferricyanide) = 147.8cal/(K*mole) = 619 J/(K*mole)
S0(ferrocyanide) = 76.6 J/(K*mole)

so i would assume delta S= -540 or something
however, i found that source 3 found a change of 17cal/(K*mole) = 71.23 J/(K*mole)
So i assume there is discussion on this matter...?

Q1: the negative sign means that the entropy decreases (more order is correct)
Q1: the magnitude of this reaction means that ferrocyanide is highly 'unstable' (less order) and that ferricyanide is highly 'stable',
Q1: (G= H-T*s) seeing that the entropy value is very high, the enthalpy can be high or low BUT there is a higher possibility that G= +, indicating that the proces is not spontanous

Q2: i recommend following sources:
http://chemed.chem.wisc.edu/chempaths/Ge…

http://www.chemtopics.com/aplab/galvanic…

hope this helps (doubt it)