So, they don’t just form very small micelles within the body of the, well, liquid of which there’s more there?
I don’t think they would. After all, olive oil and sunflower oils are themselves mixtures of several different fatty acids.
if their amounts are comparable, they will just separate according to gravity
Not if they form a solution, which I think they do. After all it’s not like if you leave a bottle of vodka alone all the water will sink to the bottom and all the ethanol will float to the top.
Ethanol has that OH group. It’s a polar molecule, and a small one. But take two pure long-chained fatty acids, mix well, and then what will happen? (I said “oils” to show I didn’t mean a “hydrophobic in polar” solution, which I hadn’t thought the question implied.)
Gasoline is an excellent example of this behavior. It consists of a mixture of many different non-polar hydrocarbons with varying densities, some of which would be gaseous outside of solution. It stays mixed indefinitely (assuming you don’t let the volatile parts escape) because separation would require a reduction in entropy.
Ethanol has that OH group. It’s a polar molecule, and a small one.
Yes, I was just mentioning it as an example.
But take two pure long-chained fatty acids, mix well, and then what will happen?
I guess they stay mixed. They are pretty similar molecules, so the forces that hold e.g. oleic acid molecules together so that it doesn’t evaporate (Van der Waals, I think?) can just as well hold oleic acid molecules to e.g. linoleic acid molecules. (Whereas since water molecules and oleic acid molecules are pretty different, the force between a water molecule and an oleic acid molecule is a lot smaller than between two water molecules or two oleic acid molecules.)
I don’t think they would. After all, olive oil and sunflower oils are themselves mixtures of several different fatty acids.
Not if they form a solution, which I think they do. After all it’s not like if you leave a bottle of vodka alone all the water will sink to the bottom and all the ethanol will float to the top.
Ethanol has that OH group. It’s a polar molecule, and a small one. But take two pure long-chained fatty acids, mix well, and then what will happen? (I said “oils” to show I didn’t mean a “hydrophobic in polar” solution, which I hadn’t thought the question implied.)
Gasoline is an excellent example of this behavior. It consists of a mixture of many different non-polar hydrocarbons with varying densities, some of which would be gaseous outside of solution. It stays mixed indefinitely (assuming you don’t let the volatile parts escape) because separation would require a reduction in entropy.
Thank you! That’s neat.
Yes, I was just mentioning it as an example.
I guess they stay mixed. They are pretty similar molecules, so the forces that hold e.g. oleic acid molecules together so that it doesn’t evaporate (Van der Waals, I think?) can just as well hold oleic acid molecules to e.g. linoleic acid molecules. (Whereas since water molecules and oleic acid molecules are pretty different, the force between a water molecule and an oleic acid molecule is a lot smaller than between two water molecules or two oleic acid molecules.)