Comment on freezing point curves

arandomthought@sh.itjust.works ⁨2⁩ ⁨years⁩ ago

• skillissuer@discuss.tchncs.de ⁨2⁩ ⁨years⁩ ago

  This is what happens when some kind of new compound is formed between these two, here it’ll be series of sulfuric acid-water complexes. Same thing happens with metals when intermetallic compounds form

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  • skillissuer@discuss.tchncs.de ⁨2⁩ ⁨years⁩ ago

    Here is a more complete chart …stackexchange.com/…/details-of-what-actually-hap…

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    • jol@discuss.tchncs.de ⁨2⁩ ⁨years⁩ ago

      I see. So these are actually many sulfuric compounds in a trenchcoat chart.

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      • skillissuer@discuss.tchncs.de ⁨2⁩ ⁨years⁩ ago

        Some of which are probably only a bit stable and so only exist in a mixture

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    • grue@lemmy.world ⁨2⁩ ⁨years⁩ ago

      Never mind between 80 and 90%, WTF is happening at 42.5%‽

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      • skillissuer@discuss.tchncs.de ⁨2⁩ ⁨years⁩ ago

        There’s a metastable phase somewhere out there and change of the most stable solid phase between 4-hydrate and 6.5-hydrate

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• Ravi@feddit.org ⁨2⁩ ⁨years⁩ ago

  My uneducated understanding is that the chart shows at which temperatures sulfuric acid freezes depending on the concentration. Also in my very basic understanding of physics and chemistry I would have thought that it’s linear or exponential or something predictable and not that jumpy.

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  • skillissuer@discuss.tchncs.de ⁨2⁩ ⁨years⁩ ago

    In normal cases you’d see two curves going away from pure compounds downwards to a common minimum, which is eutectic point

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  • marcos@lemmy.world ⁨2⁩ ⁨years⁩ ago

    Here’s what a normal curve looks like:

    i2.wp.com/…/Brine-Pro-salinity-chart.png

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• phdepressed@sh.itjust.works ⁨2⁩ ⁨years⁩ ago

  Sulfuric acid and water has various H2SO4 and H2O ratios. So like 1 H2SO4 and 6, 3, 2, or 1 H2O it also has just the H2SO4 and H2S2O7. These are present as local points within solutions and with different prominence depending on the amount of water added. These 8 different ratios each have different freezing points.

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• TheSlad@sh.itjust.works ⁨2⁩ ⁨years⁩ ago

  If I had to guess, I would assume that there are different molecular lattices that sulfuric acid and water can form at different concentrations and that these different lattices have different freezing points. I will now go look it up.

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  • skillissuer@discuss.tchncs.de ⁨2⁩ ⁨years⁩ ago

    What you’re describing are different crystalline phases of pure compounds, but this does not give you new minima, you need some new compound to form for that

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• Gladaed@feddit.org ⁨2⁩ ⁨years⁩ ago

  Physics.

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