Pressure, kbar

400 600

Pressure, kbar

Fig. 5.5 The equilibrium phase diagram for carbon

Example: At what pressure does graphite transform to diamond at room temperature? Diamond has a higher density (and consequently a lower molar volume) than graphite, and Av^g = -2x10- m /mole. Assuming that this quantity is independent of pressure, which is equivalent to assuming that the compressibilities of the two allotropes are the same, the above equation can be integrated to obtain the pressure at which the free energies of the two forms are the same:

Agd-g = 0 = Agd-g(1 atm) + (pd-g - 105)Avd-g where pd-g is the transformation pressure (in Pa) at 300 K, which is the temperature at which

Agd-g(1 atm) = 2880 J/mole and Avd-g = above equation yields:

Agd (latm)

•2x10- m /mole are specified. Using these values in the

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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