Soaps Flashcards
How are soaps made?
Through alkaline hydrolysis of fats/oils
What is the equation of the formation of a soap?
Fat/Oil + NaOH –> Glycerol + Soap
What are the 2 different parts which the soap structure is made up of?
The ionic head and covalent tail
What can the ionic head of a soap be described as?
Hydrophilic (water-loving/soluble)
What can the covalent tail of a soap be described as?
Hydrophobic (water-hating/insoluble)
What will soaps do to oil/grease?
They will attack it and break it into droplets, making it easier to clean
Describe stage 1 of cleaning a cloth with soap
If immersed into water, the oil and water cannot mix and so the oil remains on the cloth
Describe stage 2 of cleaning a cloth with soap
When soap is added, the ions dissociate, breaking them up into separate ions
Describe stage 3 of cleaning a cloth with soap
The covalent (hydrophobic) tail will dissolve in the oil/grease.
The ionic (hydrophilic) head remains in the surrounding water
Describe stage 4 of cleaning a cloth with soap
With scrubbing, the grease becomes dislodged from the surface and further ions attach themselves.
This continues until ball structures form and the grease leaves the surface.
As the carboxylate part of the soap is outside the droplet, this causes them to be a negatively charged repel.
As a result, the oil/grease is kept suspended in the water and rinsed away easily.
What is hard water?
Water containing high levels of dissolvent metal ions
What happens when soap is used in hard water?
Scum, an insoluble precipitant, is formed. To combat this, soapless detergents are used
What are soapless detergents?
Substances with non-polar hydrophobic tails and ionic hydrophilic heads like soap, however they do not form scum with hard water.
