Unit 2 Flashcards
Main uses of esters
Perfumes
Solvents
Flavourings
Perfumes
Solvents
Flavourings
Main uses of esters
Appearance of esters
Colourless liquid
Smell of esters
Sweet/fruity or nail varnish
Sweet/fruity or nail varnish
Smell of esters
Solubility of esters in water
Insoluable
Why are esters able to dissolve many compounds that arent soluable in water
Esters are not very polar, water is polar
Esters as solvents
Volatile
Low bps
Useful when rapid evaporation of solvents is required
Volatile
Low bps
Useful when rapid evaporation of solvents is required
Esters as solvents
Ester used as the solvent in nail varnish
Ethyl Ethanoate
Ethyl ethanoate
Ester used as the solvent in nail varnish
When is an ester formed
Esterfication.
When an alcohol and carboxylic acid react
What forms by esterfication
When an alcohol and carboxylic acid react
An ester
Alcohol + carboxylic acid —>
Alcohol + carboxylic acid —> ester + water
—> ester + water
Alcohol + caboxylic acid
Where does the first part of an esters name come from
The alcohol
What part of an esters name comes from the alcohol
The first part
What part of an esters name comes from the carboxylic acid
Second part
Where does the second part of an esters mare come from
The carboxylic acid
- Anol
-yl
-yl
- Anol
-Ic acid
- Ate
- Ate
- Ic acid
Alcohol functional group
- OH
Hydroxyl functional group
- OH
What molecules have a hydroxyl group
Alcohols
Carboxylic acid functional group
Carboxyl functional group, COOH
What molecules have carboxyl functional group, COOH
Carboxylic acids
Carboxyl functional group
COOH
The formation of an ester is a _______ reaction
Reversible
Esterfication is a ________ reaction
Condensation
What is produced in the formation of an ester
Water
How can we tell esterfication is a condensation reaction
Water produced
Ester link
COO or OOC
COO or OOC
Ester link
To make an ester, what must be removed from the hydroxyl group of the alcohol
A hydrogen atom
To make an ester, what must a hydrogen atom be removed from
The hydroxyl group of the alcohol
What combine to make water in the formation of en ester
The hydrogen atom and -OH of the acid
Condensation reaction
Two molecules join and produce a larger molecule while eliminating a smaller one
Two molecules join and produce a larger molecule while eliminating a smaller one
Condensation reaction
Hydrolysis
A reaction in which a molecule is split up by the chemical action of water
A reaction in which a molecule is split up by the chemical action of water
Hydrolysis
what happens when an ester is hydrolysised
An alcohol and a carboxylique acid are formed
What happens to produce an alcohol and a carboxylique acid are formed
Hydrolysis
Opposite of condensation reaction
Hydrolysis
Hydrolysis
A water molecule is added and breaks up the structure
What type of reaction is condensation
Forward
What type of reaction is hydrolysis
Reverse
Fats and oils are used _________________ to provide us with _______
Fats and oils are used in our diets to provide us with energy
_______ are used in our diets to provide us with energy
Fats and oils
Heating fats results in
Oils
Cooling oils results in
Fats
Fats are examples of _____
Esters
Solubility of fats and oils
insoluable in water
3 sources of fats and oils
Animal fat
Vegetable oil
Marine oil
Examples of animal fat
Dripping, lard, tallow
Dripping, lard, tallow
Examples of animal fat
Olives, seeds such as peanut, corn
Examples of sources of vegetable oil
Examples of sources of marine oil
Cod liver, mackerel, sardine, herring
Cod liver, mackerel, sardine, herring
Examples of sources of marine oil
Examples of sources of vegetable oil
Olives, seeds such as peanut, corn
All fats and oils are naturally occurring what
Esters
When are fats and oils formed
Condensation reactions between the alcohol glycerol and fatty acids
Systematic name for glycerol
Propane- 1, 2, 3- Tirol
Propane- 1, 2, 3- Tirol
Glycerol
State of oils at room temp
Liquid
State of fats at room temp
Solid
Oils contain more ____________ than fats
Oils contain more C=C bonds than fats
____ contain more C=C bonds than _____
Oils contain more C=C bonds than fats
Saturation
Presence of C=C bonds
Presence of C=C bonds
Saturation
What does saturation explain in fats and oils
The difference in MPs
More C=C bonds
v
More C=C bonds
v
More unsaturated
More unsaturated
v
More C=C bonds
v
Lower melting points
What do C=C bonds do to long fatty acid chains and molecules shape
Distort the long fatty acid chains
Molecule cannot pack closely together
What distorts the long fatty acid chains
Molecule cannot pack closely together
C=C bonds
What means that fat molecules can pack closely together
Less distortions as lack of C=C bonds
Result of less distortions as lack of C=C bonds
Increased BPs
Results of saturation on fat molecules
Pack closely together
Why do fats have increased BPs
They can pack closely together
Comparison of LDFs in fats and oils
The poorer packing in oils makes LDFs between the oil molecules weaker than fat molecules
How to increase the MP of an oil
Addition reaction between the double bond and hydrogen can take place
What does an addition reaction between the double bond and hydrogen can take place mean for the oil
Reduces unsaturation and causes hardening
Testing for unsaturatation
Bromine solution will quickly discolour when it reacts work unsaturated compounds
What will quickly discolour when it reacts work unsaturated compounds
Bromine solution
Fats and oils are esters, formed from a condensation reactions between the alcohol _______and different long chain _______ _______ (______ _____)
Fats and oils are esters, formed from a condensation reactions between the alcohol glycerol and different long chain carboxylic acids (fatty acids)
______________ are esters, formed from a condensation reactions between the alcohol glycerol and different long chain carboxylic acids (fatty acids)
Fats and oils are esters, formed from a condensation reactions between the alcohol glycerol and different long chain carboxylic acids (fatty acids)
Parent alcohol for au fats foils
Glycerol, propone-1,2,3 - triol
How many hydroxyl functional groups does glycerol have
3
What does glycerol have 3 of
Hydroxyl functional groups
Fatty acids
Long chain carboxylic acids ranging from C4 to C28
Eg stearic acid
Long chain carboxylic acids ranging from C4 to C28
Eg stearic acid
Fatty acids
The fatty acid molecules can be what
Saturated or unsaturated
Fats and ails formed from glycerol are known as what
Triglycerides or triesters
Triglycerides or triesters
Fats and oils
Each hydroxyl group can combine chemically with ________________
Each hydroxyl group can combine chemically with one carboxylicacid
3 carboxylie acids can react with what
A triester or triglyceride
How many acids can react with one triester
3
Hydrolysis of a fat/oil produces….
- 3 fatty acid molecules
- I glycerol molecule
What produces….
- 3 fatty acid molecules
- I glycerol molecule
Hydrolysis of fat
Effect of more carbon double bonds on fatty acids
More bent shape
Effect of more unsaturation on fatty acids
More bent shape
General formula for saturated carboxylic acids
CnH2n+1COOH
CnH2n+1COOH
General formula of saturated carboxylic acids
More carbon double bonds means ____ hydrogens
Less
Ester link
COO or OOC
COO or OOC
Ester link
Ester link also known as
Carboxylate
In glycerides, the fatty acid groups can be what 3 things
All different
Two the same
All the same
What do all proteins contain
Carbon hydrogen oxygen nitrogen
Some also contain sulfur
How do plants obtain C H and O
From carbon dioxide and water
How do animals obtain proteins
By eating plants or other animals
What happens to proteins we eat
They are converted into desireable proteins
What are proteins molecularly
Polymers
What are amino acids molecularly
Monomers
What do amino acids build
Proteins
What make up proteins
Amino acids
Amino acids functional groups
Amine group
Carboxyl group
Amine group
-NH2
-NH2
Amine group
What parts of the amino acids link to form peptide links
Co of carboxyl group
And
NH of amine group
What type of reaction is protein synthesis
Condensation
What things join to form water in protein synthesis
OH of Carboxyl group
H of amine group
What join together amino acids
Peptide/amide links
Peptide/amide link
- CONH
- CONH
Peptide/amide link
Digestion
What happens to the foods we have eaten that provides the chemical which our bodies require
What happens to the foods we have eaten that provides the chemical which our bodies require
Digestion
Protein digestion
Hydrolysis of protein molecule in our food to form amino acids
What are too large to pass through the walls of your gut
Protein molecules
What can’t pass through the walls of your gut
Proteins as they are too large
What are small enough to pass through the gut wall
Amino acids
Essential amino acids
There are 10 amino schools that humans cannot construct
They are essential in the diet
There are 10 amino schools that humans cannot construct
They are essential in the diet
Essential amino acids
What controls protein digestion
Enzymes
What bond breaks when protein is hydrolysised
C-N
What bonds to the C of the peptide link in protein hydrolysis
it becomes COOH
What bonds to the N of the peptide link in protein hydrolysis
Two Hs
Fibrous
Long fibre like structures
What bonds in the peptide link are polar
C = O
N -H
What does hydrogen bonding occur between in proteins
N-H of one peptide link and the O of the C=O in another peptide link
In proteins, What structure forms when H bonding occurs between amino groups in one chain and carbonyl group in another
Sheet structure
In proteins, what structure forms when H bonding occurs in the same chain
Helix structure
Carbonyl group
C=O
C=O
Carbonyl group
What are fibrous proteins
Tough and insoluable
What are globular proteins involved in
The regulation of life processes
Globular protein structure
Spiral chains folded into spherical shapes and soluable
Alkanols
Alkanes with a hydroxyl group
Alkanes with a hydroxyl group
Alkanols
Alkane general formula
CnH2n+2
CnH2n+2
Alkane general formula
Alkanol general formula
CanH2n+1OH
CanH2n+1OH
Alkanol general formula
First member of alcohol family to have isomers
Propanol
Isomer
Molecules with the same molecular formula but different structural formula
Molecules with the same molecular formula but different structural formula
Isomer
Primary alcohol
Only one carbon attached to the hydroxyl carbon
Only one carbon attached to the hydroxyl carbon
Primary alcohol
Secondary alcohol
Two carbons attached to the hydroxyl carbon
Two carbons attached to the hydroxyl carbon
Secondary alcohol
Tertiary alcohol
Three carbon as attached to the hydroxyl carbon
Position of hydroxyl in primary alcohol
Always at the end of a chain
What alcohols always have the hydroxyl at the end of a chain
Primary
Position of hydroxyl in secondary alcohol
Always at a non branching position on the chain
What alcohol have the hydroxyl always at a non branching position
Secondary
Position of hydroxyl in tertiary alcohol
Always at the branching position in the chain
What alcohols always have the hydroxyl at a branching position
Tertiary
Example of secondary alcohols
Cyclealkanols
Dihydric alcohol/ diol
Alcohol with 2 hydroxyl groups
Alcohol with 2 hydroxyl groups
Dihydric alcohol/ diol
Trihydric alcohol/triol
Alcohol with 3 hydroxyl groups
Alcohol with 3 hydroxyl groups
Trihydric alcohol/triol
Numbers are separated with
Commas
What does mild oxidation using warm acidified potassium dichromate solution work for
Primary and secondary alcohols
What can be oxidised using warm acidified potassium dichromate
Primary and secondary alcohols
How to oxidise primary and secondary alcohols
Warm acidified potassium dichromate
What does mild oxidation using warm acidified potassium dichromate solution not work for
Tertiary alcohols
What does mild oxidation using warm acidified potassium dichromate solution not work for
Tertiary alcohols
Colour change for primary alcohols in warm acidified potassium dichromate solution
Orange -> blue/green
Colour change for secondary alcohols in warm acidified potassium dichromate solution
Orange→ blue/green
Colour change for tertiary alcohols in warm acidified potassium dichromate solution
No change
How many stages do primary alcohols undergo s mild oxidation in
2
Stage l of primary alcohols oxidation
Loss of h by oxidising agent
Loss of h by oxidising agent
Stage l of primary alcohols oxidation
Stage 2 of primary alcohols oxidation
Gain of oxygen
What stage of mild oxidation of primary alcohols has gain of oxygen
Stage 2
What can oxidation came about by
Loss of H
or
gain of O
Primary alcohol after stage 1 of mild oxidation
Aldehyde
Primary alcohol after stage 2 of mild oxidation
Carboxylic acid
Primary alcohol → —– → carboxylic acid
Aldehyde
Primary alcohol → aldehyde → ——
carboxylic acid
→ aldehyde → carboxylic acid
Primary alcohol
How many stages of oxidation do secondary alcohols have
1
What do all the oxidation products from primary + secondary alcohols have
Carbonyl group C = O
Why can’t secondary alcohols have a secondary oxidation
There is no H attached to the c= o
Why can’t tertiary alcohols be oxidised
No H atoms attached to the hydroxyl carbon
Aldehyde aka
Alkanal
Carboxylic acid aka
Alkanoic acid
Ketones aka
Alkanones
Secondary alcohols →- – -
Ketones
Functional group of aldehydes
C=0 carbonyl
Functional group of ketones
Carbonyl c= o
Where is the carbonyl in an aldehyde
End position of longest chain, C1
Naming aldehydes
Corresponding alkane name but ending in ‘al’
Where is carbonyl in ketone
Not carbon 1
Naming ketones
Corresponding alkane but ending in one
What do aldehydes and ketones both contain
Carbonyl group
Bonding in carbonyl compounds
Polar
Pdp pdp between molecules
The bps of aldehydes and ketones will be ___than their corresponding alcohol
Lower
Volatility
The ease that a substance can evaporate
The ease that a substance can evaporate
Volatility
Mild oxidising agents
Acidified dichromate solution
Fehlings solution
Tollens solution
Alkanoic acids general formula
CnH2n+1COOH
CnH2n+1COOH
Alkanoic acids
When is food oxidised
When exposed to oxygen
Foods at greatest risk of oxidation
Fats and ails
What are antioxidants commonly used in
Vegetable oil
Animal fat
Mayonnaise
What does oxidation cause
Increase in O:H ratio
What increases O:H ratio
Oxidation
What increases when a primary alcohol is oxidised into a carboxylic acid
O:H ratio
Why do foods spoil
Became compounds in the food reach with oxygen
Undergo oxidation reactions
What do aldehydes provide in food
flavour and aroma
Result of oxidation of aldehydes
Carboxylic acids produced
Completely alter the flavour of the food
Whats happens to hydrolysis of fat in food
Fatty acids produced
Unpleasant smell
Results of oxidation of oils in food
Aldehydes and ketones produced
Rancid smell
Effects of oxidation of food
Deterioration of flavour
Loss of colour
Loss of nutritional value
Health risk
What produces aldehydes and ketones
That produces rancid smells
Oxidation of oils
What produces fatty acids
Unpleasant smells
Hydrolysis of fats
What produces carboxylic acids
Alter taste
Oxidation of aldehydes
How to prevent oxidation
Packaged foods in an oxygen free environment
Gases like CO2, N2, At are used for crisps
Add antioxidants
Antioxidant
Molecule that prevents unwanted oxidation by being oxidised easily themselves
Molecule that prevents unwanted oxidation by being oxidised easily themselves
Antioxidant
Rancicity
Deterioration of flavour
Deterioration of flavour
Rancicity
Hydrolysis of fats and oils produces…
Glycerol
And
3 fatty acids
Antioxidants in the body
they prevent harmful oxidation reactions in our bodies.
What prevent harmful oxidation reactions in our bodies
Antioxidants
What can oxidation produce
Free radicals
What can produce free radicals
Oxidation
Free radical
highly reactive species containing an unpaired electron
highly reactive species containing an unpaired electron
Free radical
What can free radicals do to food
Damage by removal of an electron
What causes damage to food by removal of an electron
Free radical
What do antioxidants do to free radicals
Transfer electron producing a neutralised free radical
What transfers an electron producing a neutralised free radical
Antioxidant
What happened to antioxidant after donating electron
Becomes a stable free radical
Itself is oxidised as it loses an election
Flavour
Combination of taste and aroma
Combination of taste and aroma
Flavour
Taste
Sweet bitter sour salty unani
What does aroma come from
Volatile molecules that travel from your mouth to receptors in your nose as you eat
What results from volatile molecules that travel from your mouth to receptors in your nose as you eat
Aroma
Volatile
Must release gaseous molecules into the atmosphere readily
Must release gaseous molecules into the atmosphere readily
Volatile
Intermolecular forces and volatility
Weaker intermolecular forces —> more volatile
What is a good indication of volatility
BP
Why is BP a good indication of volatility
As intermolecular forces are broken when a compound boils
BP and volatility
The lower the BP —> the more volatile the compound
What is the volatility of a covalent compound related to
The mass of the molecule
And
The functional group (s) in the structure
What do the mass of the molecule
And
The functional group (s) in the structure related to
The volatility of a covalent compound
______ —> weak LDFs —> easier to separate molecules —> more volatile
Lower molecular mass
Lower molecular mass —> ________—> easier to separate molecules —> more volatile
Weak LDFs
Lower molecular mass —> weak LDFs —> _______ —> more volatile
Easier to separate molecules
Lower molecular mass —> weak LDFs —> easier to separate molecules —> ______
More volatile
________ —> _______ —> ______ —> more volatile
Lower molecular mass —> weak LDFs —> easier to separate molecules —> more volatile
—- → more and stronger LDFs → more difficult to separate molecules → less volatile
Higher molecular mass
Higher molecular mass → _______→ more difficult to separate molecules → less volatile
More and stronger LDFs
Higher molecular mass → more and stronger LDFs → _________ → less volatile
More difficult to separate molecules
Higher molecular mass → more and stronger LDFs → more difficult to separate molecules → _______
Less volatile
_______ → ______→ _______ → less volatile
Higher molecular mass → more and stronger LDFs → more difficult to separate molecules → less volatile
What does the presence of a functional group mean
Makes part of the molecule polar
Usually less volatile than similar compound without the groups
What makes part of the molecule polar
Usually less volatile than similar compound workout the groups
Presence of functional groups
\_________\→ weaker intermolecular forces → easier to separate molecules → more volatile
No functional group
No functional group → ________→ easier to separate molecules → more volatile
Walker intermolecular forces
No functional group → weaker intermolecular forces → __________ → more volatile
Easier to separate molecules
No functional group → weaker intermolecular forces → easier to separate molecules → _______
More volatile
No functional group → _______→ _________ → more volatile
No functional group → weaker intermolecular forces → easier to separate molecules → more volatile
________ → stronger intermolecular forces (H bonding) → more difficult to separate molecules → less volatile
Functional groups
Functional groups → _______ → more difficult to separate molecules → less volatile
Stronger intermolecular bonding (H bonding)
Functional groups → stronger intermolecular forces (H bonding) → ______→ less volatile
More difficult to separate molecules
Functional groups → stronger intermolecular forces (H bonding) → more difficult to separate molecules → ______
Less volatile
Functional groups → ______ → ______ → less volatile
Functional groups → stronger intermolecular forces (H bonding) → more difficult to separate molecules → less volatile
Hydrocarbons polarity
Non polar
Hydrocarbon solubility
Insoluble in water
Soluable in oil
How to increase water solubility of molecules
Add more polar groups that can hydrogen bond
What can adding more polar groups that can hydrogen bond do
Increasing solubility of molecule in water
_______ = polar molecule = soluble in water
Functional groups
Functional groups = _____ = soluble in water
Polar molecule
Functional groups = polar molecule = _____\
Soluble in water
________ = non polar = insoluble in water, soluble in oil
No functional group
No functional groups = ___ = insoluble in water, soluble in oil
Non polar
No functional groups = non polar = _______
Insoluble in water
Soluable in oil
If a molecule only has C and H atoms, it will be ____
Non polar
What happens when proteins are exposed to high temperatures or extreme pH
Denatured
What determines the best cooking method and cooking time
The cut of meat
How long to cook cuts high in tough fibrous protein
Long
What happens when proteins are cooked
Heat breaks the H bonding that occurs between the protein strands of collagen
Causing them to unravel
When collagen has softened the meat becomes tender
What are proteins made from
Long amino acid chains
What can protein structures be
3d structures that form…
1 sheets
2 spirals
3 coils
What is produced when the hydrolysis of a fat happens under alkaline conditions
The salt of the carboxylic acids form
When does the salt of the carboxylic acids form
When hydrolysis of a fat happens under alkaline conditions
What are the salts produced in the hydrolysis of a fat under alkaline conditions called
Soaps
What neutralise the fatty acid molecules in some hydrolysis to form soaps
By the alkali
In some hydrolysis, what does the alkali neutralise
The fatty acid molecules
Saponification
Hydrolysis of a fat/oil undergo alkaline conditions, producing the salt of fatty acids
Hydrolysis of a fat/oil undergo alkaline conditions, producing the salt of fatty acids
Sopanification
What is the charged carboxylate group attracted to
The water molecules
Hydrophobic
Water hating
Water hating
Hydrophobic
Hydrophilic
Attracted to water
Attracted to water
Hydrophilic
What are soaps composed of
A hydrophilic head
And
A hydrophobic tail
What is composed of…
A hydrophilic head
And
A hydrophobic tail
Soap
Hydrophilic head
Carboxylate
Polar
Water soluable
Carboxylate
Polar
Water soluable
Hydrophilic head
Hydrophobic tail
Covalent hydrocarbon chain
Non polar
Oil soluable
Long chain hydrocarbon
Non polar
Oil soluable
Hydrophobic tail
What do soaps and detergents act as
Emulsifying agents
What do emulsifying agents allow for
The oils and water to mix and form an emulsion
Emulsion
Mixture of two liquids normally immisible
Mixture of two liquids normally immisible
Emulsion
What do emulsions consist of
One liquid being dispersed through the other as tiny droplets
Detergents
Very similar to soaps in structures and use
Very similar to soaps in structures and use
Detergents
What are soaps made from
Fats and oils
Detergents are made from
Crude oil
Hard water
Higher levels of minerals
Calcium and magnesium
What happens when soap is used in hard water
Scum is formed
When is scum formed
When soap is used in hard water
Scum
Insoluble precipitates formed, with Ca and Mg
Insoluble precipitates formed, with Ca and Mg
Scum
What do not form scum with hard water
Soapless detergents
What form scum
Carboxylate one in soap
And
Calcium and magnesium ions in hard water
Carboxylate one in soap
And
Calcium and magnesium ions in hard water
Scum
Detergents and precipitates
Less prone to forming precipitates than soaps
Uses for detergents
Laundry dishwashing
How do emulsion happen
Two immiscible liquids added together and shaken vigorously
Is an emulsion a mixture
Yes
Is an emulsion a solution
No
What is added to prevent water and oil layers separating
Emulsifier
What are emulsifiers added to examples
Milk
Mayonnaise
How are some emulsifiers in food made
By reacting edible oils with glycerol
Some emulsifiers in food
Glycerol backbone with 1 or 2 fatty acid molecules
One fatty acids emulsifiers
Mono - glyceride
Mono - glyceride
One fatty acid emulsifiers
Two fatty acid emulsifiers
Di-glyceride
Di-glyceride
Two fatty acid emulsifiers
Hydroxyl group and water
Hydrophilic
Fatty acid chain and water
Hydrophobic
Three types of oil
Mineral oils
Edible oils
Essential oils
Mineral oils
Derived from crude oil
Edible oils
Triglycerides, esters
Essential oils
Extracted from plants, concentrated extracts of the volatile aroma compounds
Essential oils volatility
Usually volatile
Essential oils and water
Insoluble in water
What are essential oils composed of
Organic compounds
What do essential oils not contain that perfumes do
Artificial substances
Essential oils extraction
Can be extracted from any preset of a given plant
Essential oils uses
Cleaning
Flavourings
Cosmetics
Perfumes
Are essential oils hydrophobic or hydrophilic
Hydrophobic
Essential oils smell
Very fragrant
Smelling of the plants they came from
How to extract essential oils
Steam distillation
Terpenes found in
Most common compound in essential oils
Terpenes are based on
Isoprene
2-methylbuta-1,3-diene
C5H 8
Terpenes contain carbon atoms in multiples of…
5
What are terpenes build with
Isoprene
Terpenes general formula
(C5H8)n
N is no of isoprene units
Isoprene units can be linked…
- Head to tail to form liners terpenes
- Rings to form cyclic terpenes
What reactions can simple terpenes take place in
Oxidation reaction
What can terpenes be
Alcohols
Unsaturated hydrocarbons
Ketones
Aldehydes
What can be Alcohols
Unsaturated hydrocarbons
Ketones
Aldehydes
Terpenes
Terpenoid
Terpenes containing oxygen
How do terpenes become terpenoids
Oxidation
Ultraviolet radiation
A high energy form of light, present in sunlight
A high energy form of light, present in sunlight
Ultraviolet radiation
What can exposure to UV light result in
molecules gaining sufficient energy for bonds to be broken
What can cause molecules gaining sufficient energy for bonds to be broken
Expose to UV light
Types of ultraviolet radiation
UV-A
UV-B
UV-C
UV-A
skin cancer
Longest wavelengths and releases free radicals
skin cancer
Longest wavelengths and releases free radicals
UV-A
UV-B
sunburns
Partially blocked by the ozone layer
sunburns
Partially blocked by the ozone layer
UV-B
UV-C
totally absorbed by the earths atmosphere
We encounter it only from artificial radiation sources
totally absorbed by the earths atmosphere
We encounter it only from artificial radiation sources
UV-C
What is sunburn the result of
Your skin cells committing mass suicide to protect you from their damaged DNA (that can cause cancer)
What can your skin cells committing mass suicide to protect you from their damaged DNA (that can cause cancer) cause
Sunburn
Melanin
A pigment that is produced when your skin is exposed to light
A pigment that is produced when your skin is exposed to light
Melanin
What does melanin do
Absorbs the UV radiation found in sunlight to help protect your skin
what absorbs the UV radiation found in sunlight to help protect your skin
Melanin
Result of melanin absorbing UV radiation
Skin becomes darker (a tan)
Which is a sign that it has been damaged by UV rays
What reveals the effect of photoaging
UV photography
Skin cancer
Damage to skin that causes mutations that stop the DNA functioning properly
Sun block
Inorganic ingredients reflect our scatter (block) UV radiation
Doesn’t allow UV radiation through the skin
Inorganic ingredients reflect our scatter (block) UV radiation
Doesn’t allow UV radiation through the skin
Sun block
Sun screen
Organic ingredients can absorb UV radiation, displaying it as heat
Therefore, less radiation reaches the skin
Can also include free radical scavengers
Organic ingredients can absorb UV radiation, displaying it as heat
Therefore, less radiation reaches the skin
Can also include free radical scavengers
Sun screen
When do free radicals form
When UV light breaks up a molecule
What happens when UV light breaks up a molecule
Free radicals form
How are free radicals shown
X•
X•
Free radical
steps of free radical reactions
Initiation
Propagation
Termination
Initiation
Propagation
Termination
Steps of free radical reactions
Initiation
Free radicals are formed when a molecule abalone radiation
UV light provides the energy to break the bins and form two reactive free radicals
Free radicals are formed when a molecule abalone radiation
UV light provides the energy to break the bins and form two reactive free radicals
Initiation
Propagation
Free radicals react to form further free radicals that can themselves react
This continues until all the free radicals are used up, or they come with other free radicals
Free radicals react to form further free radicals that can themselves react
This continues until all the free radicals are used up, or they come with other free radicals
Propagation
Termination
Free radicals combine, slowing the rate of and slowing the reaction
Free radicals are used up by reacting with expert
Since free radicals are required to keep this reaction going, once they have all combined the reaction will stop
Free radicals combine, slowing the rate of and styling the reaction
Free radicals are used up by reacting with eachother
Since free radicals are required to keep this reaction going, once they have all combined the reaction will still
Termination
When do alkane react with bromine
UV light, but reaction is slow
Tollens colour change
Colourless to silver
Fehlings
Blue to red
Acidified dichromate
Orange to green
How to make emulsifier with edible oils
Reacting it with glycerol
Emulsifier
- Hydrophobic part dissolves in non polar liquids
- Hydrophilic part dissolves in polar liquids
Why must potassium dichromate be acidified
To provide H+ ions
Enzymes at high temperatures
1 enzymes becomes denatured
Hydrogen bonds are broken
How to prepare standard solution
- Dissolve substance in small volume of water
- Transfer quantitatively
- Make up to the mark on flask
What does a fat produce when hydrolysed
Soap
Standard solution
A solution with an accurately known concentration
