Unit 2- SOAPS, DETERGENTS & EMULSIONS Flashcards
What are soaps made from?
Fats and oils
What are soaps also known as?
Triglycerides
How is a soap formed?
name and steps (2)
- Fats and oils can be hydrolysed (ALKALINE HYDROLYSIS) when heated with SODIUM HYDROXIDE or POTASSIUM HYDROXIDE.
- Results in the formation of GLYCEROL and a salt- SOAP
Name a common soap
Sodium stearate
Explain the structure of soap
Non-polar covalent hydrocarbon ‘tail’
Polar ionic ‘head’
What is the head’s affinity to water
HYDROPHILIC
dissolves in polar solvents such as water
What is the tail’s affinity to water
HYDROPHOBIC
repelled by water
Describe how soap works to combat grease
HYDROPHOBIC tails ‘burrow’ into droplet grease
HYDROPHILIC heads are left to face water
Non-polar substances (oil, grease) are held inside ball (a micelle) and suspended in water to be washed away
What is an EMULSION?
This suspension of small grease droplets in water is called an emulsion
What solubility rule applies here?
Like dissolves like
Why are detergent better to use hard water?
relate to structure
They have a different structure to the head
It has a senate instead of a carboxylic acid, ionic head, sap reacts with dissolved salt, producing scum detergent does not react so no scum is produced
EMULSION
contains small droplets of one liquid dispersed into another
EMULSIFIERS
Added to stabilise the emulsion from becoming unstable
Found in food and skincare
Not always wanted or needed
SYNTHETIC EMULSIFIERS
made by what and what is produced?
made by PARTIAL HYDROLYSIS of fats and oils.
Glycerol is produced.
How can you write the short hand of a soap?
/\/\/\/\/\/ - zigzag for carbons each point
