Sunday, August 2, 2009

At 25°C, the standard enthalpy for the conversion of graphite to diamond is +1.895 kJ and the change in the..

At 25°C, the standard enthalpy for the conversion of graphite to diamond is +1.895 kJ and the change in the standard entropy for this reaction is -3.363 J/K. Based on these data





A. graphite cannot be converted to diamond at 1 atm pressure.


B. diamond is more stable than graphite at all T's at one atmosphere.


C. diamond is more stable than graphite below 290°C and graphite is more stable than diamond above this T.


D. graphite is more stable than diamond below 290°C and diamond is more stable than graphite above 290°C.

At 25°C, the standard enthalpy for the conversion of graphite to diamond is +1.895 kJ and the change in the..
to happen spontaneously we want a dG = -





dG = dH - T(dS)





dG = +1.895 kJ - T( -3.363 J/K)


@ no temperature can dG = -


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A. TRUE : graphite cannot be converted to diamond at 1 atm pressure.





B. FALSE: diamond is more stable than graphite at all T's at one atmosphere.





C. FALSE: diamond is more stable than graphite below 290°C and graphite is more stable than diamond above this T.





D. FALSE: graphite is more stable than diamond below 290°C and diamond is more stable than graphite above 290°C.


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