2e) - Soaps Detergents And Emulsions Flashcards
What process are soaps produced by
Soaps are produced by the alkaline hydrolysis of edible fats and edible oils
What does hydrolysis of a typical fat or oil produce
Hydrolysis produces three fatty acid molecules and one glycerol molecule
What are the fatty acids neutralised by when a soap is made
The fatty acid molecule are neutralised by the alkali forming water soluble, ionic salts called soaps
What are ionic salts also called
Soaps
Produce a diagram of alkaline hydrolysis of edible fats and edible oils
Check jotter for answer
What substances can soaps remove
Soaps can be used to remove non - polar substances such as oil and grease
What type of tails do soaps have
Soap ions have long non-polar tails, readily soluble in non-polar compounds (hydrophobic)
What is the covalent hydrocarbon tail known as
Hydrophobic
What is the hydrophobic tail soluble in
The hydrophobic tail is non polar so soluble in non-polar substances such as oil (like dissolves like)
What is the name of the ionic head
Hydrophilic
What type of head do soap molecules have
Ionic heads that are water soluble - hydrophilic
What happens to the hydrophobic tail when removing a stain
The hydrophobic tails dissolve in the oil or grease
What happens to the hydrophilic head when removing a stain
The negatively charged hydrophilic heads remain in the surrounding water
How does agitation remove the stain
agitation causes ball like structures to form. The negatively charged ball like structures repel each other and the oil or grease is kept suspended in the water
What is the summary of how a stain is removed
The hydrophobic tails dissolves in the oil or grease. The negatively charged hydrophilic head remain in the surrounding water. Agitation causes ball like structures to form. The negatively charged ball like structures repel each other and the oil or grease is kept suspended in the water
Describe where the two parts of the soap molecule dissolve
Hydrophilic Ionic head sticks out of grease and is soluble in water
Hydrophobic tail dissolves in oil or grease as it is soluble in non polar substances
Draw a diagram showing what happens during the removal of a stain
Check jotter for answer
What is hard water
Hard water is a term used to describe water containing high levels of dissolved metal ions
What happens when soap is used in hard water
When soap is used in hard water, scum an insoluble precipitate is formed
What are soapless detergents
Soapless detergents are substances with non - polar hydrophobic tails and ionic hydrophilic heads. These remove oil and grease in the same way as soap
Why use soapless detergents
Soapless detergents do not form scum with hard water
What is an emulsifier used for
An emulsifier can be used to prevent non-polar and polar liquids separating into layers
What does an emulsion contain
An emulsion contains small droplets of one liquid dispersed into another liquid
How can emulsifiers for use in food be made
Emulsifiers for use in food can be made by reacting edible oils with glycerol
What are the hydroxyl groups in emulsifiers
The hydroxyl groups present in the emulsifier are hydrophilic
What are the fatty acids in emulsifiers
the fatty acid chains are hydrophobic.
How is a stable emulsion formed
The hydrophobic fatty acid chains dissolve in oil whilst the hydrophilic hydroxyl groups dissolve in water, forming a stable emulsion
