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How to make an 'effective' soap? - Coggle Diagram
How to make an 'effective' soap?
What is soap?
an alkali metal such as sodium or potassium with a mixture of 'fatty' carboxyl acids
result of a chemical reaction called saponification between triglycerides and a base such as sodium hydroxide
triglycerides are broken down into fatty acids and neutralized into salts by the base
this reaction also produces glycerin
a cleansing agent
produced from hydrolysis of fats
each soap molecule has a long hydrocarbon chain (tail) and carboxylate (head). In water, the sodium or potassium ions float free leaving a negatively charged head.
soap is a fatty acid of salt
can be used as cleansers and lubricants
carboxylate group is hydrophilic and interacts with water molecules via ion-dipole interactions and hydrogen bonding.
hydrocarbon chain are hydrophobic. Form micelles.
carboxylate group forms negatively charged spherical sphere
hydrocarbon chains are suspended inside sphere
as it is negatively charged, they can be washed away with water
oils and dirt get trapped inside micelles and can be washed away
fat + NaOH ---> glycerol + sodium salt of fatty acid
How do you make soap?
reacting fats/oils with with a strong hydroxide base to form glycerin and soap (salts of fatty acids)
3 base particles need to react with one fat or oil particle
have some excess fat/oil in soap so that it doesn't burn
oils to use examples - olive oil, coconut oil,
fragrance/food colouring can be added
stearic acid can be added to harden the soap
What makes a soap effective?
Soap cleans by acting as a surfactant and emulsifier. It can surround oil, making it easier to rinse it away with water.
micelles allow oil and dirt to be trapped inside so that they can be washed away
some soap molecules disrupt chemical bonds that allow bacteria, viruses and grime to stick to surfaces.
an emulsifier disperses one liquid into another immiscible liquid. Essentially, can suspend oil/dirt in a way that allows it to be removed
effective saponification and formation of miscelles
prevents oil, dirt and bacteria from sticking to a surface
Historical development of soap
soap used to be produced by cooking fatty acids (eg fat from a slaughtered sheep) with water and lye from wood ash.
soap making eventually became an art form
Soap got its name from an ancient Roman legend about Mount Sapo. Rain would wash down the mountain mixing with animal fat and ashes, resulting in a clay mixture found to make cleaning easier.
earliest production of soap dates back to 2800BC in Babylon when they noticed that mixing some materials with water worked better than water alone at cleaning
What tests can be devised to test the effectiveness of soap?
wash hands with different kinds of soap and then swab hand and put on petri dish to see how much bacteria grows
these tests test how antibacterial a soap is (how effective is it at removing bacteria
use a bacteria culture - see how much bacteria grows in the presence of homemade soap, store soap, and no soap
place hands into different contaminants, swab hands for the test petri dish, place swab petri dish with control swab, repeat but wash hands after placing hand in contaminant using different kinds of soap, would result in a number of petri dishes with different swab results. Can measure the effectiveness by how much the bacteria has grown in 48 hours
