Lecture 9

Question 1

HATS absorption, GWP and source

Answer 1

Halocarbons & atmospheric trace species.
strong IR absorption
GWP in 10s of thousands
Source–> entirely anthropogenically made

Question 2

Evidence of climate change

Answer 2

loss of ice, increased sea level, retreat of glaciers, extreme weather, ocean acidification

Question 3

What is photochemistry?

Answer 3

The chemistry that may occur under the influence of light

Question 4

When does absorption of radiation occur?

Answer 4

Only occurs if an upper energy level exists is separated by an energy difference equal to that of the incident photon.

Question 5

What is the gap in excited states? Rotational, Vibrational and Electronic

Answer 5

Rotational –> Small gab between energy level

Vibrational –> Moderate gaps in energy levels

Electronic –> Largest gaps in energy levels

Question 6

Allowed transitions

Answer 6

Happen frequently.
Ground singlet to excited singlet
Ground triplet to excited triplet

Question 7

Forbidden transitions

Answer 7

Happen rarely
Excited triplet to ground singlet

Question 8

8 ways to lose energy

Answer 8

1) dissociation
2) photoionization
3) luminescence
4) intramolecular transfer
5) energy transfer
6) physical quenching
7) direct
8) spontaneous isomerization

LOOK AT STUDY SHEET FOR CHEMICAL EQUATIONS

Question 9

Rate constant for photochemical

Answer 9

f = ∫ JoΦdλ

J=radiative flux
Φ=quantum yield
O=absorbance cross section

Question 10

Quantum yield

Answer 10

of moles of molecule formed
Φ= ———————————————-
# of moles of photons absorbed