# fitting van der waals law on real data

For an examples class on thermodynamics, I would like to fit Van der Waals law on data of real gasses, say $CO_2, H_2O_2, CH_4$.

I want to set out measurements of pressure and volume at constant temperature in a P-V diagram, and make a fit to determine the van der Waals parameters a and b. Only I have no idea where to look for experimental data.

Is such data available in databases or articles?

Would I have to extract them by hand from plots or are there (electronic) tables available? Any suggestion is welcome.

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Maybe these tables will be of use for your project thermo.sdsu.edu/testhome/Test/solve/basics/tables/tables.html – anna v Dec 3 '12 at 14:59

The best single source is at NIST. The data is located at the chemistry webbook. Once you are at that site click on formula or name under "general searches". You can not only get all the data you want in a downloadable format, it will even graph it for you

Enjoy yourself. There is no better way to learn about data than to work with it.

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@Gans Thanks for the link. If you take H2, where can you find measurements of pressure and vollume for the gas at constant temperature? I couln't find such a table under "Gas phase thermochemistry data". – sjdh Dec 3 '12 at 22:51
You have to go to the fluid properties section. – FrenchKheldar Dec 4 '12 at 6:33
@FrenchKheldar thank you. This is an wonderful resource for my classes! – sjdh Dec 4 '12 at 11:16