FRAGRANCE AND SKIN CARE

Question 1

WHERE CAN ESSENTIAL OILS B EXTRACTED

Answer 1

from plants

concentrated extracts of the aroma compounds from plants that are not water-soluble

Question 2

essential compound of essential oils

Answer 2

terpenes

Question 3

Terpenes

Answer 3

unsaturated hydrocarbons, formed by joining together units of 2-methylbuta-1,3-diene. this molecule is known as isoprene

Question 4

units that make up terpenes

Answer 4

isoprene

Question 5

Isoprene structural form

Answer 5

2-methylbut-1,3-diene

C5H8

Question 6

Isoprene to terpene

Answer 6

added together head to tail to form terpenes

both long straight chain and cyclic molecules can be formed

Question 7

terpene oxidised

Answer 7

after being oxidised within plants, terpenes are responsible for the flavours of many distinct spices such as ginger, cloves and cinnamon

Question 8

terpene oxidised examples

Answer 8

Vannilin

Limonene

Cinnamaldehyde

Thymol

Citronellal

Cittronellol

Question 9

UV from sun

Answer 9

high energy form of light

Question 10

Increasing types of UV radiation

Answer 10

UVA
UVB
UVC

Question 11

UV does what to skin

Answer 11

break down collagen, which can lead to premature ageing

Question 12

Block UV

Answer 12

Sunblock by preventing UV being absorbed

Question 13

Over exposure to UVB

Answer 13

Sunburn, skin cancer

Question 14

UVA and skin cancer

Answer 14

Indirectly breaking down DNA in a process that involves free radicals

Question 15

Free radicals

Answer 15

highly reactive atoms that have on unpaired electron

Question 16

why are free radicals unstable

Answer 16

tendency for unpaired electrons to pair up and so free radicals react quickly

Question 17

How are radicals formed

Answer 17

covalent bond is broken by energy supplied by UV light. Due to their reactivity, they can cause chain reactions, as they often react to produce other free radicals. 3 stage process

Question 18

Stage 1 free radical formation

Answer 18

Initiation

Dot next to each Br indicated one unpaired electron each has from shared pair electrns of covalent bond. Dividing one BR molecule produces 2 highly reactive radicals.

When UV light is needed to begin the process, further reactions do not need UV light, and so chain can continue in darkness

Question 19

Stage 2 free radicals

Answer 19

Propagation

Highly reactive radicals formed can remove atoms from other stable compounds to re-establish stable covalent bonds. This reaction produces a new free radical.

The new radical can inturn react with another Br molecule. This is also known as propagation step as generates a radical; product

Question 20

Stage 3 radical formation

Answer 20

termination

chain reaction will only end when a reaction takes place in which no new radicals are formed. this can occur whenever free radicals react with each other

Question 21

free radical scavangers

Answer 21

chemicals (usually vitamins, minerals or enzymes) that react and destroy free radicals

desirable to protect our skin and our food

Question 22

where are free radical scavangers found

Answer 22

cosmetics and in some foods and plastics

Question 23

free radical and radical scavanger react

Answer 23

prevent chain reaction occuring

Question 24

many free radical scavangers are

Answer 24

antioxidants

Question 25

green tea scavanger

Answer 25

polyphenols