Soaps Flashcards
How are soaps made?
They are made from the hydrolysis of fatty acids using alkanals as the hydrolysing agent, which nutralises the fatty acids. This is called alkaline hydrolysis and produces 1 gycerol molecule and ionic salts, also known as 3 soap molecules.
What are the main parts of a soap molecule?
The hydrophobic, covalent tail and the hydrophylic ionic head (COO^- Na^+, no covalent bond in the head because it is an ionic bond). Metal has the negative charge.
How do soaps work?
Due to the ionic head and covalent tail, the soap can make oil and water mix. The greese in the water will dissolve the covalent tail (like dissolves like, non-polar), leaving the negative charged head facing out towards the water. Agitating the water causes the oil to break up into smaller masses, forming micells. The negative heads will repel other micells, keeping them from forming a larger mass. If drawing a diagram, always draw TWO micells and label.
What does the suspension of water in the oil create?
An Emulsion. This is a fine disperion of one liquid in another which is immisscible.
What is hard water and what happens when you use a soap in it?
Hard water is water that has the presence of calcium ions and magnesium ions. These react with soap to form a scum, so a soapless detergent should be used so that a scum does not form.
What is an emulsifier/emulsifying agent?
A substance that stabalises an emulsion, allowing two liquids to be miscible (mix).
What is a surfactant?
A compound that reduces the surface tensions between two liquids or a solid
