Examples of Chemical Equilibrium Calculations

We are now prepared to use thermodynamics to make chemical equilibrium calculations. The following examples demonstrate some of the possibilities. 

Example 9.1 Calculate the equilibrium sublimation pressure above diamond at 298.15 K. 

The sublimation pressure will be small so that j = 1. Also, at the low pressure involved, we can let T — 1. Hence 

This extremely low pressure corresponds to much less than one gaseous carbon atom (on the average) in the universe at a time. 

With our choice of standard states and the low pressure involved, we can write 

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