Unit 2-Soaps, Detergents And Emulsions Flashcards
How are soaps made?
Alkaline hydrolysis of fats and oils
What else is made in the following reaction? Fat or oil + Sodium Hydroxide –> Soap + ????
Glycerol
Describe the structure of a soap molecule.
Long non-polar covalent hydrocarbon ‘tail’ and a polar, ionic ‘head’.
What word can be used to describe the tail of a soap molecule which is repelled by water?
Hydrophobic
What word can be used to describe the polar ionic head of a soap molecule which can dissolve in water?
Hydrophilic
How does the structure of soaps allow it to clean?
During cleaning using soaps the hydrophobic tails dissolve in a droplet of oil or grease, whilst the hydrophilic heads face out into the surrounding water
What word is used to describe small grease droplets suspended in water?
Emulsion (micelle)
How does a detergent clean?
Hydrophobic tails would dissolve into the fat-soluble dirt.
Hydrophilic heads would dissolve in water
Advantage of using detergents over soaps
Do not cause scum with hard water
What is hard water?
Water with high levels of dissolved metal ions
Why are emulsifiers added to foods?
To prevent the oil and water from separating and stop the food from spoiling.
Identify the hydrophobic and hydrophilic parts of these emulsifiers.
Hydroxyl groups are hydrophilic, whilst fatty acid chains are hydrophobic.
How are emulsifier made?
Edible oil is reacted with glycerol
