A Talk with dirt and cloth!!!

Dirt: Hello cloth, I feel so proud to meet you.^^
Cloth: Oh my god, I felt so sad to meet you…T.T
Dirt: Why? you should happy because you have a new friend and you don’t think you can chuck me out.( laugh in one's beard)
Cloth: Who say can’t?
Dirt: Me…I’m a pertinacity dirt and not like normal dirt. I’m the king of dirt.(hahah)
Clot: You’re too puerility! Now, my big brother detergent is coming now to clean away you this dirt! Even though is god of dirt also needed to run away. So before he come, you better run away from me now!(laughing)(hahah…)
Dirt: Don’t scare me, I won’t leave away!!!!



Finally, detergent was rescue the clot and kills the dirt. The white cloth returns back into pure white in color!!!














Soap and detergent



Soap and detergent are chemicals that can be remove strains in our cloths. Both are salts of a carboxylate groups. For the salts of carboxylate group, normally it will have 12-18 carbons. Besides that, carboxylate group are amphiphilic which containing a hydrophilic head and hydrophobic tail. As a matter of fact, soap and detergent have slightly different in functions and the chemical structure. For soap, they do not have charged group at the end of the molecules, just like –COO^-, Na⁺. In other hand, for detergent it normally will end with a polar sulfate ion and form soap-like micelles in water.








Structure of soap


























Structure of detergent











Micelle in water




















Micelle in water






The mechanism of how soap and detergent remove dirt actually is the same.


1. When soap or detergent pours into water with a dirt cloth, the ons will move freely.
2. At the same time, soap will reduce the surface tension of water to cause the wetting of greasy surface.
3. The hydrophobic part of anions will dissolve in the grease and penetrate into the greasy stains whereas the hydrophilic part will still remain in the water. This form an image of micelle.
4. Now, the greasy stains are surrounded by the negatively charged head of soap anions.
5. By the movement of water and rubbing, scrubbing or heating, the grease together with the soap anions will loosened and lofted off the surface of cloth, this is because the force of attraction between water molecules and the negatively charged head of soap on the grease surface.
6. Now, the grease coved by negative end of anions becomes suspended in the water.
7. Agitation of water will break up the grease into smaller droplets.
8. Droplets of grease will repel each other because of the negatively charged covered to their surface.
9. When rinse the cloth with water, grease droplets will be remove.

Although the mechanism of soap and detergent to remove dirt are the same, but there are different in different type of water, especially in hard water. Hard water is an aqueous solution that presents of mineral salts, for example calcium (Ca), magnesium (Mg), iron (Fe) and manganese (Mn).

When soap pours into hard water, a sticky insoluble soap scum will form when calcium ions or magnesium ions react with soap. For example:

2C₁₇H₃₅COO^-(aq) + Ca²⁺ → ( C₁₇H₃₅COO)2Ca(s)
Insoluble calcium stearate (scum)

2C₁₇H₃₅COO^-(aq) + Mg²⁺ → (C₁₇H₃₅COO)2Mg(s)
Insoluble mgnesuim stearate (scum)

After the scum form, it will reduce the amount of soap available for cleaning. In addition, the scum will clings to the object and make the cloth dirtier. But there are different in detergent, detergent won’t form any scum with ions in hard water.

Soap and detergent have their own advantages and disadvantages also.

For soap:

- It is biodegradable, which does not cause any pollution to the environment.
- It is clean effectively in soft water.
- It does not clean effectively in hard water.

For detergent:

- It is effective in soft and hard water.
- It is highly soluble in water.
- It is cheaper then soap.
- It is non- biodegradable.
- The softening agent (phosphate) in detergent will cause water pollution.


So....what should i use now???Is it a soap or a pollute detergent???


!!!OH MY GOD!!!