unit 2

Question 1

what is UV light?

Answer 1

high energy form of light present in sunglight

Question 2

what can UV light do to molecules?

Answer 2

provide sufficient energy to break bonds within molecules and free radicals are formed

Question 3

what effects does UV light have on the skin?

Answer 3

causes subrun
accelerates ageing of the skin

Question 4

what can prevent UV light reaching the skin?

Answer 4

use sun-block

Question 5

how are free radicals formed?

Answer 5

when UV light energy breaks bonds within molecules

Question 6

what are free radicals?

Answer 6

atoms or molecules that are highly reactive due to the presence of unpaired electrons

Question 7

steps of a free radical chain reaction

Answer 7

initiation
propagation
termination

Question 8

what are free radical scavengers?

Answer 8

molecules that react with free radicals to form stable molecules

Question 9

where can free radical scavengers be found?

Answer 9

cosmetics
food products
plastics

Question 10

what are essential oils?

Answer 10

concentrated extracts of the volatile, non-water soluble aroma compounds from plants

Question 11

where are essential oils used?

Answer 11

perfumes
cosmetic products
cleaning products
flavourings in foods

Question 12

what are terpenes?

Answer 12

isoprene units joined together
unsaturated

Question 13

systematic name for isoprene?

Answer 13

2-methylbuta-1,3-diene

Question 14

draw the structure of isoprene

Answer 14

search it upppppppppppp

Question 15

what can terpenes be oxidised to produce?

Answer 15

aromas of spices

Question 16

what are proteins involved in?

Answer 16

maintenance and regulation of life processes

Question 17

what are enzymes?

Answer 17

biological catalysts

Question 18

what are proteins made of?

Answer 18

amino acids

Question 19

what functional groups do amino acids contain?

Answer 19

amine group
NH2
carboxyl group
COOH

Question 20

how are proteins made?

Answer 20

condensation

Question 21

what functional group is found in a protein?

Answer 21

peptide link
-CONH-

Question 22

what are essential amino acids?

Answer 22

must be required from the diet as the body cannot make them

Question 23

what happens to proteins during digestion?

Answer 23

hydrolysis

Question 24

structural formula amino acid
structural formula protein

Answer 24

search it upppppppppp

Question 25

protein structure

Answer 25

long-chain molecules forming spirals held together by intermolecular bonding

Question 26

what happens when a protein is heated?

Answer 26

intermolecular bonds are broken and proteins change shape (denature)

Question 27

what is the result of a protein denaturing in food?

Answer 27

change in texture when its cooked

Question 28

how is soap produced?

Answer 28

alkaline hydrolysis of edible fats and oils

Question 29

what does alkaline hydrolysis produce?

Answer 29

3 fatty acid (soap) 1 glycerol

Question 30

how are the 3 fatty acid molecules changed into soap?

Answer 30

neutralised by the alkali forming ionic salts called soaps

Question 31

soap structure?

Answer 31

TAIL non-polar soluble in grease/oil hydrophobic HEAD ionic soluble in water hydrophilic negatively charged

Question 32

soap usage steps

Answer 32

1 - when mixed with grease/oil the hydrophobic tail dissolves in grease and hydrophilic head dissolved in water 2 - agitation results in ball-like structures with the hydrophobic tails on inside (vise versa) 3 - negatively charged micelles repel each other and oil/grease is suspended in water

Question 33

what is hard water

Answer 33

water containing high levels of dissolved metal ions

Question 34

how is scum formed?

Answer 34

mixing together hard water and soap

Question 35

what do soapless detergents do?

Answer 35

do not form scum with hard water (same structure as soap)

Question 36

what is an emulsifier?

Answer 36

prevent non-polar and polar liquids separating into layers

Question 37

what is an emulsion?

Answer 37

contains small droplets of one liquid dispersed in another liquid

Question 38

how are emulsifiers used?

Answer 38

reacting edible oils with glycerol only 1or2 fatty acid groups are linked to the glycerol (works same as soap too)

Question 39

functional group found in an ester?

Answer 39

ester link -COO-

Question 40

what are esters used for?

Answer 40

flavourings fragrances solvents for non-polar compounds

Question 41

how are esters formed?

Answer 41

condensation alcohol+carboxylic acid

Question 42

what is a condensation reaction?

Answer 42

two molecules are joined together with the elimination of a small molecule (usually water)

Question 43

what is hydrolysis?

Answer 43

a molecule reacts with water to break down into smaller molecules

Question 44

how are fats and oils created?

Answer 44

condensation of glycerol (alcohol) and 3 fatty acids (carboxylic acid)

Question 45

glycerol name?

Answer 45

propane-1,2,3-triol

Question 46

glycerol structure

Answer 46

search it uppppppppp

Question 47

why do oils have a lower melting point than fats?

Answer 47

contain C=C meaning they cannot pack closely together so weaker intermolecular forces fats contain no C=C

Question 48

how to test for the degree of saturation?

Answer 48

titration - the greater number of C=C present, the more bromine solution can be decolourised

Question 49

what are fats and oils?

Answer 49

concentrated source of energy essential for the transport and storage of fat-soluble vitamins in the body

Question 50

metal oxide + carboxylic acid =

Answer 50

salt + water

Question 51

metal hydroxide + carboxylic acid =

Answer 51

salt + water

Question 52

metal carbonate + carboxylic acid =

Answer 52

salt + water + carbon dioxide

Question 53

types of alcohol

Answer 53

primary secondary tertiary

Question 54

primary alcohol identification

Answer 54

the hydroxyl group is attached to a carbon which is attached to 1 other carbon

Question 55

secondary alcohol identification

Answer 55

the hydroxyl group is attached to a carbon which is attached to 2 other carbon

Question 56

tertiary alcohol identification

Answer 56

the hydroxyl group is attached to a carbon which is attached to 3 other carbon

Question 57

oxidation ratio

Answer 57

increase in the oxygen to hydrogen ratio

Question 58

reduction ratio

Answer 58

decrease in the oxygen to hydrogen ratio

Question 59

aldehyde and ketone functional group

Answer 59

carbonyl --C=O

Question 60

oxidising agents for primary and secondary alcohols

Answer 60

acidified potassium dichromate hot copper oxide

Question 61

acidified potassium dichromate colour change

Answer 61

orange - green

Question 62

hot copper oxide colour change

Answer 62

black - copper red

Question 63

oxidising agents for aldehydes

Answer 63

acidified potassium dichromate fehling's solution tollens' reagent

Question 64

fehling's solution colour change

Answer 64

blue - brick red

Question 65

tollens' reagent colour change

Answer 65

colourless and clear - silver mirror