AP BIOLOGY

Detailed explanation-1: -Answer 2: Hydrophobic just means ‘afraid of water’. So something that is hydrophobicrepels water. Oil is hydrophobic, therefore oils or Vaseline are put in lotions or sunscreen to repel water (such as sweat and pool/ocean water).

Detailed explanation-2: -White petroleum jelly is a non-polar hydrocarbon hydrophobic and insoluble in water, glycerol (not a hydrocarbon but an alcohol) is the opposite: petroleum jelly is so strongly hydrophilic that by continuous absorption of moisture from the air, it produces the feeling of wetness on the skin, similar to the greasiness.

Detailed explanation-3: -The main ingredient in Vaseline is petroleum. Petroleum forms a tight waterproof barrier when applied to the skin. This can help the skin retain its moisture and act as an at-home treatment for dry skin.

Detailed explanation-4: -Hydrophobes are nonpolar molecules and usually have a long chain of carbons that do not interact with water molecules.

Detailed explanation-5: -Lipids are hydrophobic means water hating. They are water insoluble. Lipids are non-polar molecules while water is polar molecule, so there is no way for water to attach to a lipid molecule. Instead, the non-polar lipids will bind to themselves, which is why oils and fats form droplets on the surface of water.