Most dirt on your body is nonpolar, and is trapped in oil residue on your skin. What type of liquid is oil? (polar or nonpolar) show your calculations.
Would water rinse off this dirt, since it is in oil? Why or why not?
Does soapy water rinse off this dirt?
Soap: how does it work?
Oil is a long chain hydrocarbon, nonpolar.
Water is polar. What do you think?
Soap is a long chain oil with a POLAR end.
To determine whether oil is polar or nonpolar, we can consider its molecular structure. Oil is primarily composed of hydrocarbons, which consist of carbon and hydrogen atoms bonded together. Because carbon and hydrogen have similar electronegativities, the bonds between them are considered nonpolar. Therefore, it can be concluded that oil is a nonpolar liquid.
Now, let's discuss whether water can rinse off dirt trapped in oil residue. Since water is a polar molecule, it will not mix well with nonpolar substances like oil. Therefore, if dirt is trapped within an oil layer on your skin, water alone will not effectively rinse it away because it cannot dissolve the nonpolar oil layer.
However, soapy water can effectively remove dirt trapped in oil residue. Soap molecules contain both polar and nonpolar regions. The polar "head" of a soap molecule is attracted to water molecules (hydrophilic), while the nonpolar "tail" is attracted to oil molecules (hydrophobic). When soapy water is applied to the skin, the soap molecules form micelles, which surround and encapsulate the oil droplets. The polar heads of the soap molecules face outwards, allowing them to interact with water, while the nonpolar tails remain attracted to the oil. As a result, the dirt particles trapped in oil are emulsified and can be rinsed away with water.
So, to summarize, water alone cannot effectively rinse off dirt trapped in oil, but soapy water can because soap molecules have the ability to interact with both water and oil due to their molecular structure.