Test Bank Answers Chapter 22 Environmental Chemistry 1074

CHAPTER 22

Environmental Chemistry

CHAPTER STUDY OBJECTIVES

1. Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere

SKILLS TO MASTER: Calculating atmospheric residence times, naming and drawing CFCs, writing reactions explaining acid rain and photochemical smog, calculating an AQHI, explaining atmospheric warming.

KEY CONCEPTS: The structure of the atmosphere is based on how temperature varies with altitude.

1. Explain the relevant chemical reactions occurring in the aquatic phase

SKILLS TO MASTER: Calculating alkalinity, interpreting a Pourbaix diagram, calculating BOD and COD, using MAC and TDI values.

KEY CONCEPTS: Lakes with high carbonate concentration are somewhat protected from acidification. The oxidative or reducing power of a body of water is quantified by the value of pE.

1. Describe some of the major pollutants of interest in the environment

SKILLS TO MASTER: Recognizing hydrophilic versus hydrophobic pollutants, drawing and naming PCBs, dioxins and furans, calculating TEQ values.

KEY CONCEPTS: We need to be aware of the many emerging contaminants in the environment Metal ions are often in the form of complexes in the environment. The relative toxicities of many compounds can be quantified using Toxic Equivalency Factors. Many pollutants of concern are lipophilic.

1. Describe how chemical species move through the environment

SKILLS TO MASTER: Using Henry’s law to calculate the partitioning of a pollutant between water and air, using a distribution coefficient to do the same between water and sediments, using a bioconcentration factor to do the same between water and a living organism.

KEY CONCEPTS: Pollutants move through the environment and become distributed in the atmosphere, hydrosphere and Biosphere Less polar (more lipophilic) compounds tend to bioccumulate and biomagnify.

Multiple Choice QUESTIONS

1) What is the oxygen concentration in typical lake water?

a) 0.001%

b) 0.01%

c) 0.1%

d) 1.0%

Difficulty: Medium

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

2) What drives forces for the atmospheric circulation?

a) Humidity

b) Pressure and Radiation

c) Wind

d) Solar radiation and earth rotation

Difficulty: Medium

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere

Section Reference: 22.1 Atmospheric Chemistry

3) What is the region of the atmosphere from 20-50km above the earth surface?

a) Stratosphere

b) Thermosphere

c) Mesosphere

d) Troposphere

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

4) What is the region of the atmosphere from 0-20km above the earth surface?

a) Stratosphere

b) Thermosphere

c) Mesosphere

d) Troposphere

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

5) Calculate the atmospheric lifetime of unknown gas if the mass is 4.50 x 10¹⁸ kg and it is emitted into the atmosphere at a rate of 412 x10¹⁸ kg y⁻¹.

a) 0.011 year

b) 1 year

c) 10 years

d) 100 years

Difficulty: hard

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

Feedback: The lifetime (τ) of a compound is proportional to the amount of it in the atmosphere (Q) and inversely proportional to the rate (R) at which it is emitted into (or removed from) the atmosphere

6) Which among the following is a secondary source of pollution?

a) NO₂ and HNO₃ formed from NO.

b) Ozone (O₃ ) formed from photochemical reactions of nitrogen oxides and VOCs.

c) Sulfuric acid droplets formed from SO₂ and nitric acid droplets formed from NO_2.

d) Sulfates and nitrates aerosols (e.g. ammonium (bi) sulfate and ammonium nitrate) formed from reactions of sulfuric acid droplets and nitric acid droplets with NH_3.

e) All of the above

Difficulty: medium

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

7) Where can you find inert CFCs, that are resistant to attack by molecules, radicals, or the UV radiation?

a) Stratosphere

b) Thermosphere

c) Mesosphere

d) Troposphere

Difficulty: Medium

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

8) Ozone is formed from the dissociation of molecular oxygen by short wavelength UV radiation in the upper stratosphere.

a) True

b) False

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

9) Which of the following steps of a reaction can lead to ozone depletion?

a) CFC l ₃ (UV)→ CFCl₂ + Cl₂

b) OCl ^• + O ^• ⟶ Cl₂ + O ₂

c) OCl • + O • ⟶ Cl • + O ₂

d) O₃ ⟶ O₂+ O 2

Difficulty: Hard

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

Feedback: The series of oxygen-only reactions known collectively as the Chapman cycle. These explain the presence of ozone in the stratosphere. “M” is any molecule in the atmosphere and serves to carry away excess energy so a bond can form.

10) Chapman cycle consists of some steps that create ozone, and some that destroy it.

a) True

b) False

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

11) Name the following contaminant

a) Chlorobromoethane

b) Chlorodibromomethane

c) Chlorobromomethane

d) Chlorodibromoethane

Difficulty: medium

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

12) Calculate the concentration of rainwater that is in equilibrium with air that has an SO₂ concentration of 3.2 ppm and the K_H is (1.0 M/atm).

a) 3.2 M

b) 0.32 M

c) 3.2 x10 ^-6 M

d) 3.2 x10 ^-9 M

Difficulty: Hard

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

Feedback: If a compound exists in the troposphere, and if it is soluble in water, then it likely exists in rainwater as well. This is a manifestation of Henry’s Law.

13) Calculate the pH of rainwater that is in equilibrium with air that has an SO₂ concentration of 4 ppm when K_a = 0.017?

a) 3.75

b) 3.50

c)3.58

d)3.60

Difficulty: Difficult

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere.

Section Reference: 22.1 Atmospheric Chemistry

14) What is one of the main causes of photochemical smog in big cities?

a) Depletion of ozone

b) Automobile exhausts

c) Use of painting products

d) All of the above

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions and phenomena occurring in the stratosphere and troposphere

Section Reference: 22.1 Atmospheric Chemistry

15) The COD is determined by titrating and oxidizing the organic matter in a water sample using a strong oxidant.

a) True

b) False

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemistry

16) Which of the following molecules is found in the water and is a natural source, also added to drinking water promote dental health?

a) Fluoride (F ⁻)

b) Lead (Pb)

c) Zinc (Zn)

d) Chloride(Cl^-)

Difficulty: medium

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase

Section Reference: 22.2 Aquatic Chemistry

17) Which of the following molecules is found in the water and also leaches from plumbing materials?

a) Fluoride (F ⁻)

b) Lead (Pb)

c) Zinc (Zn)

d) Chloride (Cl^-)

Difficulty: medium

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase

Section Reference: 22.2 Aquatic Chemistry

18) Benzo(a)pyrene leach is contaminant that come from plastic in water distribution systems is known to cause

a) Bone degeneration

b) Brain aneurysm

c) Cancer

d) Blood poisoning

Difficulty: medium

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase

Section Reference: 22.2 Aquatic Chemistry

19) The maximum acceptable concentrations (MAC) for Benzo(a)pyrene in Canadian drinking water is 0.00004 mg L−1. The TDI value is 0.0667 μg kg−1 d−1. If you drank 3 L per day of water contaminated with 0.00030 mg Benzo(a)pyrene per litre, calculate your daily intake. Have you exceeded the TDI? Assume you weigh 75 kg, and that this drinking water is your only exposure to Benzo(a)pyrene.

a) Its 0.012 Benzo(a)pyrene μg kg⁻¹ d⁻¹. This is far below the TDI.

b) Its 0.12 Benzo(a)pyrene μg kg⁻¹ d⁻¹. This is above the TDI.

c) Its 0.000012 Benzo(a)pyrene μg kg⁻¹ d⁻¹. This is far below the TDI.

d) Its 1.2 Benzo(a)pyrene μg kg⁻¹ d⁻¹. This is above below the TDI.

Difficulty: Hard

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemistry

Feedback: Use the volume of water, the lead concentration, and the body mass to calculate the daily intake, then compare to the TDI. The daily intake per unit body weight is therefore = the [mg/day]/ body weight.

20) Where is a source of 2,4-Dichlorophenol contamination?

a) Drinking water disinfection by-product

b) Runoff from use as an herbicide

c) Runoff rom agricultural use

d) Plastic in water distribution systems

Difficulty: medium

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemistry

21) Groundwater is water within the earth’s crust, lying just below the surface.

a) True

b) False

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemistry

22) What type of pollution forms from water pollution in which plants well nourished by pollutants thrive at the expense of aquatic animals?

a) Biological contamination

b) Thermal pollution

c) Sedimentation pollution

d) Eutrophication

Difficulty: medium

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemistry

23) Which of the following is a chemical pollutant responsible for Eutrophication?

a) Benzo(a)pyrene

b) Atrazine

c) Phosphates

d) Lead

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemistry

24) What is the name of an aquatic contaminant that cause Minamata disease that developed from eating fish?

a) 2,4-dichlorohenoxyacetic acid

b) 2,4-Dichlorophenol

c) Tetrachloroethylene

d) Mercury

Difficulty: Hard

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemistry

25) Most jurisdictions in the world define microbiological, chemical, and radiological contaminants in drinking water in published guidelines referred to as

a) Total Daily Intake

b) Daily dose

c) Maximum acceptable concentration

d) LD₅₀

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemist

26) What is the best chemical to be used for determining COD chemical oxygen demand using titration through a strong oxidizing reagent?

a) Potassium permanganate

b) Sulphuric acid

c) Phosphoric acid

d) Sodium oxalate

Difficulty: easy

Learning Objective: Explain the relevant chemical reactions occurring in the aquatic phase.

Section Reference: 22.2 Aquatic Chemist

27) Metal ions are often in the form of complexes in the environment.

a) True

b) False

Difficulty: easy

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

28) What is the name of the following pesticide?

a) Pyrobenzene

b) 2,4-Dichlorophenoxyacetic acid

c) Atrazine

d) Glyphosate

Difficulty: medium

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

29) What is the name of the following insecticide?

a) Pyrobenzene

b) Dibenzofuran

c) Glyphosate

d) Biphenyl

Difficulty: medium

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

30) Name the following insecticide structure.

a) 1,2-dichlorodibenzo-p-dioxin

b) 1,3-dichlorodibenzo-p-dioxin

c) 1,7-dichlorodibenzo-p-dioxin

d) 1,6-dichlorodibenzo-p-dioxin

Difficulty: medium

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

31) The relative safety of many compounds can be quantified using Toxic Equivalency Factors.

a) True

b) False

Difficulty: easy

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

32) Which compound is not lipophilic?

a)

b)

c)

d)

Difficulty: difficult

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

Feedback: meaning that they readily dissolve in fatty tissues, and that they bioaccumulate, meaning that their concentrations tend to increase moving up the food chain.

33) What is the physiochemical property of this structure?

a) Hydrophilic

b) Lipophilic

c) Hydrophobic

d) Neutral

Difficulty: Hard

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

34) What is the main use of paraquat?

a) Insecticide

b) Pesticide

c) Germicide

d) Herbicide

Difficulty: medium

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

35) Which of the following is a contaminant found in water and is very toxic?

a) Zinc

b) NaCl

c) Arsenic

d) Copper

Difficulty: easy

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

36) The common salt that is used to melt winter ice can seep into the ground with spring thaws and rains and cause chemical pollution.

a) True

b) False

Difficulty: easy

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

37) Name the following insecticide.

a) Dichlorodiphenyltrichloroethane

b) Dichlorodiphenyltrichloromethane

c) Dichlorodiphenyltrichloroethyne

d) None of the above

Difficulty: medium

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

38) Organic compounds containing chlorine atoms bonded to benzene rings are degraded easily in the environment.

a) True

b) False

Difficulty: easy

Learning Objective: Describe some of the major pollutants of interest in the environment.

Section Reference: 22.3 Pollutants in the Environment

39) What is the name of the chemical that is commonly found in polar bears in the arctic?

a) Zinc

b) Dibenzofuran.

c) Lead

d) Polychlorinated biphenyl 

Difficulty: medium

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

40) When pollutants move from one environment to another they are subjected to the following:

a) Degradation

b) Bioaccumulation

c) Biomagnification

d) Bioconcentration

e) All of the above

Difficulty: medium

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

41) What is the term that describes the process by which substances used in farming or produced in industrial waste make their way into and up the food chain?

a) Degradation

b) Bioaccumulation

c) Biomagnification

d) Bioconcentration

e) All of the above

Difficulty: medium

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

42) What is the term that examines the increased presence of a particular substance inside a single organism?

a) Degradation

b) Bioaccumulation

c) Biomagnification

d) Bioconcentration

e) All of the above

Difficulty: medium

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

43) For the Dichlorodiphenyltrichloroethane (DDT), the Henry’s law constant is K_H=2.23x10^-3 mol/L Pa. Assume DDT is present in water at a concentration of 0.0003 mg/ L, and is in equilibrium with the air above the water. Calculate the partial pressure of this DDT in the air (in Pa).

a) 3.79x10^-7Pa

b) 3.79x10^-5Pa

c) 8.46x10^-10Pa

d) 8.46x10^-7Pa

Difficulty: Hard

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment.

Feedback: We will first have to convert the concentration into units that match those of the Henry’s Law constant. The concentration unit conversion requires the molecular weight of this DDT is 354.46 g/mol. calculate the partial pressure from Henry’s Law.

44) Dichlorodiphenyltrichloroethane (DDT), the Bioconcentration factor (BCF) of DDT is 89.010 in case of liver tissue of the fish exposed to 30 days. Assume that lipids have a density of 864 g/ L and that the fish are 2.3 % by weight lipids. Express your answer in mg (kg lipids)−1 and in mg (kg fish)−1. Assume DDT is present in water at a concentration of 0.0003 mg/ L. Calculate the concentration of the DDT found in fatty tissue of the liver of this fish swimming in this water.

a) 5.58x10^-4 mg (kg fish ) −1

b) 5.31x10^-4 mg (kg fish ) −1

c) 6.58x10^-4 mg (kg fish ) −1

d) 4.58 mg (kg fish ) −1

Difficulty: Hard

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

Feedback: BCF is the ratio of pollutant concentration in fatty (lipid) tissues of the living organism divided by the aqueous phase concentration.

45) How can you indicate the lipophilicity in the tissue?

a) Degradation

b) Bioaccumulation

c) Biomagnification

d) Bioconcentration

e) Octanol/water partitioning

Difficulty: medium

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

46) The hydrosphere is a major reservoir for pollutants and their metabolites.

a) True

b) False

Difficulty: easy

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

47) Indicate which pollutant consist of the highest water/octanol ratio value?

a) Atrazine

b) 2,4-Dichlorophenol

c) Gylcophosate

d) 2,4-Dichlorophenoxyacetic acid

Difficulty: easy

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

48) PCBs tend to adsorb onto sediments or solids suspended in the water. These are taken up by aquatic organisms such as zooplankton, which in turn are eaten by fish.

a) True

b) False

Difficulty: easy

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

49) What is the hard rigid shell of our planet, consisting of the surface layer which forms earth’s crust?

a) Hydrosphere

b) Lithosphere

c) Stratosphere

d) Troposphere

Difficulty: easy

Learning Objective: Describe how chemical species move through the environment.

Section Reference: 22.4 Transport of Pollutants in the Environment

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