[LHM]

1. Which substance is most likely to be soluble in a nonpolar solvent?
A) glucose B) graphite C) lithium fluoride D) sulfur

The answer's D. I know that it's not C because lithium fluoride is polar, but why is it not A or B?

22. Which statements are true?
1. S^o values for all elements in their standard states are positive.
2. S^o values for all aqueous ions are positive.
3.  :delta: S^o values for all spontaneous reactions are positive.

A) 1 only B) 1 and 2 only C) 2 and 3 only D) 1, 2, and 3

I see why 3 is false. But the answer's A, and I don't see how 1 is true and 2 is false? I'd really appreciate it if someone could explain.

41. Which two species react spontaneously?
A) Cu(s) + Ag⁺ B) Br₂(l)
C) H₂O (l) + Ca²⁺ D) Au(s) + Mg²⁺


I figured that it wouldn't be D since gold isn't very reactive. Out of the rest of the options though, why is it A?

[Jorriss]

Lets start with one.

Glucose is polar, lithium fluoride is ionically bonded, it's not polar. Graphite would likely be soluble too, the question is which is most likely, if that makes sense. Do you have any reasons why sulfur might be more soluble in a non polar solvent than graphite?

[LHM]

Well doesn't sulfur normally form those rings like S₈?
And graphite's normally in layers from what I can remember.
Does that have something to do with it?

[opti384]

Maybe the reason why graphite is not soluble in nonpolar solvent is that graphite forms an covalent bond between carbon atoms. Because the strength of the covalent bond is too strong, graphite is not soluble in either polar and nonpolar solvent. For sulfur, I think it could melt in nonpolar solvents because it forms molecular crystals.

[eleven6eleven]

For 41, it's A because copper is higher than silver on the reactivity series:

http://www.chemos.co.uk/Reactivity.htm