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![](/common/images/spacer.gif) The ratio of the number of ortho- to para-hydrogen molecules at equilibrium
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Department: | Chemical Engineering |
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![](/common/images/spacer.gif) 2006-11-09
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![](/common/images/spacer.gif) The notebook presents the computation of ortho- to para-hydrogen molecules at equilibrium. The calculation indicates that at low temperatures and at equilibrium, the equilibrium mixture approaches 100% para-H2 while at sufficiently high temperatures the gas contains 75% ortho-H2. When a gas is frozen, we get a metastable equilibrium with 75% ortho-H2. In fact, in the absence of a catalyst, the half-life for conversion to para-H2 from ortho-H2 is very long. A plot of p-H2 versus temperature is given in the notebook. This plot is similar to Figure 4.5 page 127 in G. Nicolis, Dynamique Chimique, Thermodynamique, cinétique et mécanique statistique, Dunod, Paris 2005.
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![](/common/images/spacer.gif) ortho- to para-hydrogen, metastable equilibrium, statistical thermodynamics, equilibrium composition in p-H2 and o-H2
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| para-ortho-H2.nb (30.1 KB) - Mathematica Notebook |
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