Unit 2 Flashcards
The negatively-charged ball-like structures…
repel each other and the oil or grease is kept suspended in the water
free radicals are…
atoms or molecules that are highly reactive due to the presence of unpaired electrons
the negatively charged hydrophilic heads…
remain in the surrounding water
the solubility, boiling point and volatility of a compound can be predicted by considering…
- O-H or N-H bonds, which implies hydrogen bonding
- molecular size which would affect london dispersion forces
- polarity of solute and solvents
Edible fats and edible oils are…
esters from the condensation of glycerol and three carboxylic acid molecules
the carboxylic acids are known as ‘fatty acids’
carboxylic acids can react with…
bases
proteins are the major…
structural materials of animal tissue and are also involved in the maintenance and regulation of life processes. Enzymes are proteins which act as BIOLOGICAL CATALYSTS
Amino acids are…
relatively small molecules which all contain an amino group -NH2 and -COOH
The link which forms between two amino acids is known as a…
peptide link/amide link
Essential amino acids are…
amino acids that our body cannot make. It is essential that these amino acids are present in our diet
when proteins are heated…
The intermolecular bonds are broken which changes shape of the protein (denature)
PS. it causes texture in food to change when cooked
oxidation is an…
increase in the oxygen to hydrogen ratio
Reduction is an…
decrease in the oxygen to hydrogen ratio
fats and oils are…
- a concentrated source of energy
- essential for the transport and storage of fat-soluble vitamins in the body
the equation for the breakdown of an ester by water is…
Ester + Water <=> alcohol + carboxylic acid
a “reversible reaction”
An ester link is…
-COO-
When soap is used in hard water…
scum, an insoluble precipitate is formed
hydrolysis produces…
3 fatty acid molecules and 1 glycerol molecule
an emulsion contains…
small droplets of one liquid dispersed in another liquid
hot copper oxide or acidified dichromate solution can be used to oxidise…
- primary alcohols to aldehydes then to carboxylic acid
- secondary alcohols to ketones
in a hydrolysis reaction…
a molecule reacts with water to break down into smaller molecules
alcohols can be classified as…
primary/secondary and tertiary
OH groups make alcohols…
polar and this allows hydrogen bonding to take place
in a condensation reaction…
two molecules are joined together with the elimination of a small molecule
esters are formed by…
a condensation reaction between an alcohol and a carboxylic acid
esters are used as…
flavourings and fragrances. They are also used as solvents for non-polar compounds that do not dissolve in water
to determine whether a compound is unsaturated or saturated you can use…
bromine solution
compounds containing at least 1 carbon-carbon double bond are described as…
unsaturated
free radical scavengers are added to many products including…
- cosmetics
- food products
- plastics
an emulsifier can be used to prevent…
non-polar and polar liquids separating into layers
soaps are produced by the…
alkaline hydrolysis of edible fats
hard water is a term used to describe water containing…
high levels of dissolved metal ions
isomers are…
- compounds with the same molecular formula but different structural formula
- may belong to different homologous series
- usually have different physical properties
compounds containing only single carbon-carbon bonds are described as…
saturated
compounds containing double bonds can take part in…
an addition reaction
in an addition reaction…
two molecules combine to form a single molecule
free radical scavengers are…
molecules that react with free radicals to form stable molecules and prevent a chain reaction from occuring
terpenes are based on…
(C5H8)n, where n is the number of terpene units joined together
isoprene molecules can form…
linear or ring structures
what stage is this representing?
H* (g) + Cl* (g) -> H - Cl (g)
H* (g) + H* (g) -> H - H (g)
Cl* (g) + Cl* (g) -> Cl - Cl (g)
Termination stage
what stage is this representing?
H - H (g) + Cl* (g) -> H - Cl (g) + H* (g)
H* (g) + Cl - Cl (g) -> H - Cl (g) + Cl* (g)
Propagation stage
free radical chain reactions include the following steps:
- initiation
- propagation
- termination
what stage is this representing?
Cl - CL (g) -> Cl* (g) + Cl* (g)
Initiation stage
soaps can be used to…
remove non-polar substances such as oil and grease
the hydrophobic tail…
dissolve in the oil or grease
soap ions have…
- long hydrophobic nonpolar tails
- ionic heads that are water soluble (hydrophilic)
agitation causes…
ball-like structures to form
when UV light breaks bonds…
free radicals are formed
sun-block/sunscreen products prevent…
UV light reaching the skin
UV light can provide…
sufficient energy to break bonds within molecules. This causes sunburn and accelerates ageing of the skin
terpenes are the…
key components in most ESSENTIAL OILS
essential oils are…
widely used in perfumes, cosmetic products cleaning products and as flavouring in foods
essential oils are…
extracts of the volatile, non-water soluble aroma compounds from plants
antioxidants are…
- molecules that prevent unwanted oxidation reactions occuring
- substances that are easily oxidised, and oxidise in place of the compounds they have been added to protect
- can be identified as the substance being oxidised in a redox equation
with an aldehyde, orange acidified dichromate solution turns into what colour…
turns green
with an aldehyde, clear, colourless tollens’ reagent…
forms a silver mirror
with an aldehyde, blue fehling’s solution forms…
a red precipitate
a ketone functional group is…
C=O
The double bonds in fatty acid chains…
prevent oil molecules from packing closely together. The more double bonds present, the weaker the van der waals forces of attraction.
I.e: the more unsaturated it is, the lower the melting points
edible oils have…
lower melting points than edible fats
esters can be hydrolysed to produce an…
alcohol and CARBOXYLIC ACID
aldehyde functional group is…
CHO
tertiary alcohols cannot…
be oxidised using these oxidising agents
black copper (II) oxide forms a…
brown solid, and orange dichromate turns green
ultraviolet (UV) radiation is a…
high energy form of light, present in sunlight
