skin care

Question 1

what is uv radiation?

Answer 1

high energy form of light present in sunlight

Question 2

what can uv light provide?

Answer 2

enough energy to break chemical bonds in molecules in the skin and DNA

Question 3

what can uv radiation cause?

Answer 3

sunburn
skin cancer
photoaging

Question 4

describe sunblock/sunscreen

Answer 4

physical barrier on the skin to protect from uv radiation

white pigments reflect UV radiation

Question 5

what can damage from UV radiation start?

Answer 5

a free radical chain reaction

Question 6

3 stages of uv radiation

Answer 6

initiation
propagation
termination

Question 7

what is a free radical?

Answer 7

is an atom or molecule with one or more unpaired electrons

Question 8

Describe step 1 of uv radiation

Answer 8

its a mixture of two products
break weakest covalent bond
Br-Br to produce 2Br’ a free radical

Question 9

describe step 2 of uv radiation

Answer 9

the free radical reacts with other molecules to become stable again
it produces more free radicals which reacts with the molecule again
Produces a free radical
Br’+C6H14= HBR+ C6H13’
C6H13 + Br-Br= C6H13Br + Br’

Question 10

describe step 3 of uv radiation

combinations from products of step

Answer 10

2 free radicals join to form stable molecules and no other radicals are produced
2Br’=Br-Br
Br’+C6H13=C6H13Br
C6H13’+C6H13’=C12H26