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Given the reaction of diamond converting to graphite

2C (s diamond)==>2C (s graphite)
 
Determine ΔG at 298L and determine if this reaction is spontaneous or not. What does the ΔG say about the rate of this reaction?
 
ΔH°f (C (s) diamond)=1.9kJ/mol
S°(C (s) diamond=2.38J/mol
S°(C (s)graphite)=5.74J/mol

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J.R. S. | Ph.D. in Biochemistry--University Professor--Chemistry TutorPh.D. in Biochemistry--University Profes...
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∆G says nothing about the rate of the reaction.  It only provides information about spontaneity.
∆G = ∆H - T∆S
Plug in values (be careful of units; note ∆H is in kJ/mol and others are J/mol).
Do this for the forward and reverse reactions AS WRITTEN.
If ∆G is negative, the reaction is spontaneous.
 
You probably realize that diamonds are made from solid carbon, but it takes a very long time under a great deal of pressure. Thus, the reaction of C(s) ==> diamond(s) would be spontaneous but the rate of reaction is extremely so.  The numerical answer you get from the above equation should agree with this.