MChem Master of Chemistry Environmental Chemistry

Question 1

What is the primary chemical reaction responsible for the formation of tropospheric ozone in urban smog?

Accepted Answer

Photolysis of NO2 followed by O + O2 → O3

Answer

Direct emission of O3 from vehicles

Answer

Reaction of SO2 with sunlight

Answer

Oxidation of methane by OH radicals alone

Question 2

Which greenhouse gas has the highest global warming potential (GWP) on a per-molecule basis over a 100-year horizon?

Accepted Answer

Sulfur hexafluoride (SF6)

Answer

Carbon dioxide (CO2)

Answer

Methane (CH4)

Answer

Nitrous oxide (N2O)

Question 3

What chemical process converts dissolved CO2 in the ocean to carbonic acid, contributing to ocean acidification?

Accepted Answer

CO2 + H2O → H2CO3

Answer

CO2 + 2H2O → CH4 + O2

Answer

CO2 + NaCl → Na2CO3 + Cl2

Answer

CO2 + CaCO3 → Ca(HCO3)2

Question 4

What is the Henry's Law constant used to describe in environmental chemistry?

Accepted Answer

The equilibrium partitioning of a chemical between air and water

Answer

The rate of photodegradation of pollutants

Answer

The adsorption of contaminants onto soil particles

Answer

The biodegradation rate of organic compounds

Question 5

Which process describes the increase in concentration of persistent pollutants (e.g., PCBs) at higher trophic levels in a food chain?

Accepted Answer

Biomagnification

Answer

Bioaccumulation

Answer

Biodegradation

Answer

Biotransformation

Question 6

What is the role of hydroxyl radicals (•OH) in tropospheric chemistry?

Accepted Answer

They act as the atmosphere's primary oxidant, initiating degradation of VOCs and methane

Answer

They catalyze stratospheric ozone depletion

Answer

They are the main cause of acid rain

Answer

They absorb UV radiation in the stratosphere