| MadSci Network: Chemistry |
When you find that theory (sugar dissolves in vegetable oil, because it has parts which can interact well with the lipid part of the vegetable oil)does not agree with the facts (in your experience, your experiment, the sugar does not dissolve well in the vegetable oil), you go with the facts and find out what is wrong with the theory.
The previous explanation (theory) is not complete. The description about salt dissolving is correct, but something must be added. The salt ions can "hide" in the water, because the water can separate them from one another in the crystal. The water is very good at overcoming the forces that tightly hold the ions together in the crystals.
The oil, because it is a lipid ("fat like"), is much different than water and cannot separate the ions. Salt does not dissolve in oil.
It is true that sugar is made of carbon, hydrogen and oxygen and is not composed of ions, but the sugar molecules are not very "fat like" and they are tightly held to one another in the sugar crystals. The oil just cannot separate them, or is very poor at doing it, so only a very small amount of the sugar will dissolve. The oil is just very poor at separating molecules or ions that are tightly held together. You might try to dissolve some candle wax (in small pieces) in vegetable oil. The molecules in the candle wax are not held together very tightly.
Dr. Jerry Franzen
Try the links in the MadSci Library for more information on Chemistry.