Cfe Higher - Chemistry - Unit 2: Nature's Chemistry - Soaps, Detergents and Emulsions

Question	Answer
How are soaps formed?	Hydrolysis of fats and oils
How many moles of Glycerol and fatty acids are firmed with each mol of hydrolysed fat or oil	1 mol glycerol 3 mols fatty acids
Manufacture of Soaps	Fats/oils boiled with sodium/potassium hydroxide.
What role does the alkali play in the manufacture of soaps	Catalyses the hydrolysis reaction and then neutralises the fatty acids.
Structure of Soaps	Ionic hydrophillic head non-polar hydrophobic hydrocarbon chain
How does soap cleanse?	Hydrophobic tails bury themselves int he grease, hydrophillic heads remain in water. Soap ions dislodge the grease from surface of plate and splits it up into tiny droplets.
What prevents the grease from joining together again?	Surrounded by negatively charged soap ions therefore they repel eachother.
How are detergent ions different to soap ions?	They can be used in hard water
What is hard water and where is it normally found?	hard water is water containing Mg2+ and Ca2+ ions normally found in the south of England
Why do soap ions not work so effectively in hard water?	They react with the Mg and Ca ions to form insoluble salts known as scum
What is an emulsion?	The mixture of two immiscible liquids which have been vigorously shaken
What is an emulsifier?	A compound similar in shape to soaps and detergents added to emulsions to prevent the two liquids from separating into distinct layers.
Structure of Emulsifiers	Hydrophillic head and hydophobic tail. Esters of glycerol and fatty acids.

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	Created by scarlettjaynem about 10 years ago