Date post: | 19-Jan-2016 |
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Soap
Objectives
1.• Learn how to make soap
2.• Understand how soaps work
3.• Have a soap making competition
Making soaps
• Soaps are made from fatty acids and metallic ions such as sodium
• They are made by combining strong alkalis such as sodium or potassium hydroxide with oils or fats.
What is a lipid?
What is a fatty acid?Can you give them IUPAC names?
Chemical Reaction
• 2 stages• 1. fatty acids are separated from their glycerol
chain• 2. The alkali reacts with the fatty acid
producing a metalic carboxylate salt and water.
Diagram
How soaps work
2.
• The soap disocciates into sodium and carboxylate ions:• Which is positive and which negative? (see slide 7)
2.
• Carboxylates have hydrophobic and hydrophilic ends• What does this mean?• Which end is hydrophobic and which is hydrophilic?
3. • The hydrophilic ends come together to form clusters called micelles in water. • Soap is an emulsifying agent: what does this mean?
1.
How soaps work 2
5.
• The carboxylate chains form micelle balls with hydrophilic surfaces
• All have the same charge – what is it and what does this mean one micelle ball does to another?
6.
• Grease and oil attract dirt. Grease and oil are non- polar so they will not dissolve in what?
• But they will mix with the non-polar hydrophobic carbon chains of the carboxylate ions and micelles, so the grease and dirt is ………..
Lab session
• We will make soap in the lab using coconut oil.• But we could use other oils • We could add essential oils to provide scent• And colours• We could mould to different shapes
Competition
• Each table must design and develop their own soap. Consider these
• Brand name• Shape• Colour• Scent• Target market• Publicity materials• Cost to make and to be sold• Packaging
Rubricmarks Product quality
Marks x 2Costs Marketing strategy
1 Failed None None
2 Basic hard soap A cost given A target market identified
3 Some attempt to colour or scent and brand name
A price worked out Some advertising material
4 Good product with an element missing
Economics explained with some questions
Clear campaign strategy
5 Scented shaped coloured soap atractively packaged
Cost and price clearly explained
Effective marketing strategy supported by quality publicity