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I have only a high school understanding of chemistry, so please bear with me and my ham-fisted question. I’m trying to understand the carbon content in vegetable oil. I get that various oils have differing densities, so the measure needs to be “by weight”. Molecular weight doesn’t help, I need the measure in useful measures like “grams per liter” (preferred).

(Also of note, I’m not certain I got the right tags)

UPDATE: Based on feedback, I looked up oil production per hectare to determine an oil type. It appears that the highest production per hectare (which feeds into the analysis I'm working on) for grain-based oils is rapeseed. For tree-based fruits, it's oil palm, and then there's algae oil.

I'm trying to establish how much carbon is embodied in the oil production of one acre of crop (a bit of information that probably would have been helpful to say first).

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    $\begingroup$ It's different depending on particular oil, also what you prefer isn't by mass. $\endgroup$
    – Mithoron
    Feb 11 at 16:23
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    $\begingroup$ Which vegetable oil ? There exist so many vegetable oils ... $\endgroup$
    – Maurice
    Feb 11 at 16:28
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    $\begingroup$ Two key problems: there are lots of different oils so no general answer is possible; most "oils" contain more than one chemical component (even ignoring impurities). So you need to be specific in asking the quetion. $\endgroup$
    – matt_black
    Feb 11 at 16:34
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    $\begingroup$ However, all the main oil molecules are long-chain (say like en.wikipedia.org/wiki/Omega-3_fatty_acid with 18 carbons on the backbone), with mostly hydrogen filling it out, and an occasional OH or O group added on. So roughly 2-plus a bit hydrogen per carbon, ignore the OH or O, and you get a carbon mass ration of a bit less than 12/14, or 80 wt.% carbon (rounding down). $\endgroup$
    – Jon Custer
    Feb 11 at 16:47
  • $\begingroup$ @JonCuster, this is a sufficient answer for me (presuming it's reasonably accurate across the oils I identified in the update). Turn it into an answer and I'll accept it. $\endgroup$
    – J.D. Ray
    Feb 11 at 18:33
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Vegetable oils are mainly made of glycerol esters of oleic acid, linoleic acid and palmitic acid. For example, the fatty acids extracted from olive oil are a mixture of $74$% oleic acid, $11$% palmitic acid, and $10$% linoleum acid, plus 5% other acids. These proportions are average values that may change from one sample to the next one.

The mass proportion of carbon atom is $77.2$ % in glycerol trioleate, $78.3$ % in glycerol trilinoleate, and $75.8$ % in glycerol tripalmitate

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