Section 8 consumer products Flashcards
What are soaps
They are molecules formed from an alkaline hydrolysis of edible fat or oil, with a hydrophobic tail and a hydrophilic head.
Alkaline hydrolysis equation
Fat molecule + alkali —-> soap + glycerol
Which alkali is typically used in alkali hydrolysis
Sodium
How many soaps does one fat molecule produce in alkaline hydrolysis
3 soaps + 1 glycerol
Soaps definition
A molecule with an ionic hydrophilic head and a non polar hydrophobic tail, formed from the alkaline hydrolysis of an edible fat or oil.
Molecules that soaps can remove
Non polar molecules due to the non Polar hydrophobic tail, which dissolves itself in the non polar molecules,
Cleaning action of soap
- The non polar hydrophobic tail will dissolve in the non polar substance.
- The ionic hydrophilic head will remain in the polar substance.
- When agitated the non polar molecules break apart into smaller globules.
- These tiny globules with their negative ions repel each other and are then easily washed away.
Hard water
Water that contains high concentration of magnesium and calcium ions.
How is hard water formed
Through ions being dissolved out of the soil by rainwater and into drinking supplies.
Scum definition
A precipitate formed between a soap and hard water.
Lather
Where large group of molecules break down into tiny globules due to the use of a soap and agitation.
Soapless detergents
Detergents are molecules with a non polar hydrophobic tail and an ionic hydrophilic head, which don’t form scum in hard water.
Advantage of detergents over soaps.
Detergents don’t form scum in hard water.
Difference in the structure of detergents and soaps
The structure of the negative ion is different, detergents : S=O=O O- soaps C=O O-
Emulsion
Where a non polar liquid and polar liquid have tiny droplets dispersed in each other.
How are emulsifiers formed
Edible oils + 2glycerol —> emulsifier
Emulsifiers structure
A glycerol molecule with 1 or 2 fatty acid chains.
How do emulsifiers work
The free hydroxyl groups remain in the polar molecule, and the fatty acid hydrophobic tails dissolves in the non polar substance and keeps them dispersed in each other.
Antioxidant properties
Reducing agents
Easily oxidised
Prevent unnecessary oxidation’s of food occurring.
Why are antioxidants added to food
To prevent a rancid flavour from developing, due to unwanted oxidation’s occurring
Essential oils definition
Concentrated extracts of volatile and non water soluble compounds from plants.
Properties of essential oils
Volatile and non water soluble
Key component of essential oils.
Terpenes
What are terpenes made up of
Isoprenes
Isoprenes chemical name
2-methylbuta-1,3- diene
How are distinctive aromas formed
Oxidation of terpenes
How do you calculate the number of isoprenes
Count carbons divide by 5
What affects the retention time in gas chromatography
Molecular size and polarity.
Gas chromatogram
A diagram which shows the intensity of molecules on the y axis and the retention time on the x axis
Rules of gas chromatography
As the polarity increases the retention time increases.
As the molecular size increases the retention time increases.
Retention time definition
The time taken for the substance to travel through the apparatus.
How are essential oils separated from plants
Steam distillation
Steam distillation experiment
A Bunsen heats up a boiling tube with a pipe into a beaker with purified water in the bottom of it, the source of essential oils has steam passed over it which extracts the essential oils.
A wet pater towel is used to ensure that none of the essential oils go back.
UV radiation
A high energy form of light found in sunlight
Important properties of UV radiation
Able to break apart the the bonds between atoms and form free radicals.
Effects of UV radiation
Sunburn and accelerated skin ageing
Free radicals def
Atoms or molecules which are extremely reactive due to unpaired electrons.
How are free radicals represented
By a dot next to the chemical
Free radical chain reaction stages
Initiation
Propagation
termination
Initiation stage
A stable molecule will break down into two free radicals
Stable —>free radical + free radical
Uv light is switched on
Propagation stage
A free radical and a stable react of form a free radical and a stable, then the free radical and the stable react to form a free radical and a stable
uv light is switched off
Free radical x + stable x—-> free radical y + stable y
Free radical y + stable Z —-> free radical x + stable A
Termination stage
Free radicals bond together to form stable products, large number of different combinations.
Uv light is switched off
Free rad + free rad —> final product.
Free radical scavengers
Molecules which react with free radicals to form stable molecules.
How do you protect the skin from uv light
Sun block - prevents uv light from reaching the skin, and prevents the formation of free radicals.
Free radical scavengers - react with free radicals to form stable and harmless products.
Antioxidant example
Vitamin C
