Which of the following compounds would one expect to be liquid (with the lowest density) at room temperature?
|A||A saturated triglyceride|
|B||A monounsaturated triglyceride|
|C||A polyunsaturated triglyceride|
|D||None of the above, as all would be solids at room temperature.|
The major factor that determines whether or not a triglyceride will be solid or liquid at room temperature is the level of saturation of the fatty acids it contains. A completely saturated triglyceride is completely “filled” with hydrogen atoms, and is therefore linear in shape. This allows the molecules to pack closely and easily together, which results in a solid phase physical structure. We would call this type of molecule a “fat” or “saturated fat”. A point of unsaturation occurs where a carbon-carbon double bond exists, and hydrogen atoms could potentially be added by hydrogenation. The more points of unsaturation, the more “kinks”, or bends, the fatty acid will have. This makes packing together difficult, and we obtain a liquid, usually called an “oil”.