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posted by  edelpink on 11/5/2009 1:20:49 AM  |  status: Live  |  Earned Karma: 60

Thermodynamics/ LifeSaver!!! Please Help!!

Course Textbook Chapter Problem Needs by
Thermodynamics N/A Phase Equilibrium N/A 11/6/2009 at 11:00:00 AM
Question Details:

The density of diamond is 3.52 g/cm3 and that of graphite is 2.25 g/cm3. At 25°C the Gibbs energy of formation of diamond from graphite is 2.900kJ/mol. At 25°C what pressure must be applied to bring diamond and graphite into equilibrium??


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posted by kwyjibo on 11/5/2009 5:56:19 PM  |  status: Live
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Response Details:
dG = -SdT + VdP + udN

dG = VdP at constant T and N

2.900 kJ = (1/2.25 - 1/3.52) cm3/ g * ΔP
2.900 kJ/mol = 0.160353535 cm3/ g * ΔP

ΔP = 18.0850394 kJ*g/[mol/cm3]
ΔP = 18.0850394 kJ*g/[mol/cm3] *(1000 J/1kJ)*(1 mol/12 g)*(100 cm/1m)^3
ΔP = 1.50708662e9 = 1.51 x 109 Pa
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