MChem Master of Chemistry Environmental Chemistry 3

Question 1

Which process in the nitrogen cycle converts nitrate (NO3−) back to N2 gas under anaerobic conditions?

Accepted Answer

Denitrification

Answer

Denitrification is the microbial reduction of NO3− to N2 (and N2O) under anaerobic conditions, closing the nitrogen cycle.

Question 2

What are persistent organic pollutants (POPs) characterized by?

Accepted Answer

Resistance to degradation, lipophilicity, long-range transport, and toxicity

Answer

POPs are defined by their persistence, bioaccumulation in lipids, potential for long-range atmospheric transport, and adverse health and ecological effects.

Question 3

In advanced oxidation processes (AOPs) for water treatment, what is the primary reactive species generated?

Accepted Answer

Hydroxyl radical (•OH)

Answer

AOPs generate highly reactive •OH radicals through processes like UV/H2O2, O3/H2O2, or Fenton reactions to oxidize recalcitrant organic contaminants.

Question 4

What is phytoremediation in environmental chemistry?

Accepted Answer

Use of plants to accumulate, degrade, or stabilize contaminants in soil or water

Answer

Phytoremediation uses hyperaccumulator plants (e.g., Thlaspi caerulescens for Zn/Cd) to extract, contain, or break down contaminants in contaminated environments.

Question 5

What does the BOD (Biochemical Oxygen Demand) measurement indicate about a water sample?

Accepted Answer

The amount of oxygen consumed by microorganisms to degrade organic matter

Answer

BOD measures the oxygen consumed by microorganisms when decomposing organic matter in water over 5 days at 20°C, indicating organic pollution load.

MChem Master of Chemistry Practice Test

MChem Master of Chemistry Practice Test

MChem Master of Chemistry Environmental Chemistry 3