Final answer:
Saturated fatty acids contain only single bonds, while unsaturated fatty acids contain one or more double bonds along the hydrocarbon chain. The composition and structure of saturated and unsaturated fatty acids result in differences in Van der Waals forces.
Step-by-step explanation:
Saturated fatty acids are fatty acids that contain only single bonds along the length of the carbon chain, while unsaturated fatty acids contain one or more double bonds along the hydrocarbon chain. Saturated fatty acids have straight chains, while unsaturated fatty acids have bent chains due to the presence of double bonds.
The difference in composition between saturated and unsaturated fatty acids lies in the number and location of double bonds. Saturated fatty acids contain only single bonds, and their carbon atoms are fully saturated with hydrogen atoms. In contrast, unsaturated fatty acids contain one or more double bonds, which result in fewer hydrogen atoms bonded to the carbon chain.
Van der Waals forces are intermolecular forces that occur between molecules. In saturated fatty acids, the van der Waals forces are stronger due to the absence of double bonds, resulting in a straight, tightly packed structure. In unsaturated fatty acids, the presence of double bonds introduces kinks in the chain and weakens the van der Waals forces, leading to a more loosely packed structure.