Soaps, Detergents And Emulsions Flashcards
(21 cards)
How are soaps produced?
Alkaline hydrolysis of edible fats and oils
What does the alkaline hydrolysis produce?
What happens to the fatty acids?
The hydrolysis produces 3 fatty acid molecules and one glycerol molecule
Fatty acids are neutralised by the alkali forming water soluble ionic salts called soaps
What can soaps be used to remove?
Non-polar substances like oil or grease
What are soaps made up of?
A long non-polar hydrocarbon tail and an ionic head
Are the tails in soap hydrophobic or hydrophilic?
Hydrophobic as they’re soluble in non-polar compounds so it doesn’t dissolve in water but dissolves is oil/grease
Are the heads in soap hydrophobic or hydrophilic?
Hydrophilic as they’re soluble in polar compound so they dissolve in water(negatively charged)
Are the soap molecules negative or positively charged?
Negatively as they can dissolve in the grease
What part of the soap molecule enters the oil/grease droplet?
The hydrophobic tail(dissolves in the droplets)
What does agitation cause?
It causes ball-like structures to form(globules)
What happens after agitation?
The negatively charged globules/ball-like structures repel each other and the oil/grease is kept suspended in the water
This prevents the oil droplets from re joining and helps disperse the oil as they’re broken up into ball-like structures
Where do the negatively charged ionic heads remain?
In the surrounding water of the grease globules
What is hard water?
Water that contains high levels of dissolved metal ions
What happens when soap is used in hard water?
An insoluble precipitate(scum) forms
What are soap less detergents?
Substances with a non-polar hydrophobic tail and an ionic hydrophilic head
Do soap less detergents form scum in hard water
No they don’t
How do soap less detergents work?
They remove oil and geese in the same was as soap does
What is an emulsifier used for?
To prevent non-polar and polar liquids from separating into layers
What is an emulsion?
A liquid that contains small droplets of another liquid dispersed in it
How are emulsifiers for use of food made?
By reacting edible oils with glycerol
How many fatty acids do the molecules formed in emulsifiers contain?
One or two fatty acids
What are the parts of an emulsifier?
They hydroxyl groups which are hydrophilic and can dissolve in water
The fatty acid/s which are hydrophobic and dissolve in oil
Together they form a stable emulsion
