What can be said about the spontaneity of this reaction? cdiamond→cgraphite

The forward reaction of C (diamond) -> C (graphite) is spontaneous at 298 K

Gibbs free energy is the maximum possible work given by chemical reactions at constant pressure and temperature. Gibbs free energy can be used to determine the spontaneity of a reaction

If the Gibbs free energy value is <0 (negative) then the chemical reaction occurs spontaneously. If the change in free energy is zero, then the chemical reaction is at equilibrium, if it is> 0, the process is not spontaneous

Free energy of reaction (G) is the sum of its enthalpy (H) plus the product of the temperature and the entropy (S) of the system

Can be formulated: (at any temperature)

or at (25 Celsius / 298 K, 1 atm = standard)

ΔG ° reaction = ΔG ° f (products) - ΔG ° f (reactants)

Under standard conditions:

∆G ° = ∆H ° - T∆S °

The value of °H ° can be calculated from the change in enthalpy of standard formation:

∆H ° (reaction) = ∑H ° (product) - ∑ H ° (reagent)

The value of ΔS ° can be calculated from standard entropy data

∆S ° (reaction) = ∑S ° (product) - ∑ S ° (reagent)

If we look at the standard free Gibbs energy for the transformation from diamond to graphite at 298 K:

∆G ° rxn = -2.90 kJ

then a negative value indicates that reaction

C (diamond) -> C (graphite) occurs spontaneously (forward reaction)

Delta H solution  

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an exothermic reaction  

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as endothermic or exothermic  

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an exothermic dissolving process  

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