Review Quiz: Air Quality And Environment! Hardest Trivia
This exam was offered as part of A&WMA's online course, "GENAQ-100E: Environmental Practices Review Specialty Course: Air Quality" in 2008.
Questions and Answers
- 1.
Air is a non-homogeneous mixture of gases, solid particles and liquids.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Air is considered a non-homogeneous mixture because it is composed of various gases, such as nitrogen, oxygen, carbon dioxide, and trace amounts of other gases. Additionally, air can contain solid particles, such as dust, pollen, and pollutants, as well as liquid droplets, like water vapor. These components are not uniformly distributed throughout the air, leading to its non-homogeneous nature. Therefore, the statement that air is a non-homogeneous mixture is correct.Rate this question:
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- 2.
Most household cleaning products and paints contain:
- A.
Metals
- B.
Volatile organic compounds
- C.
Carbon dioxide
- D.
Nitrogen oxides
Correct Answer
B. Volatile organic compoundsExplanation
Volatile organic compounds (VOCs) are commonly found in household cleaning products and paints. VOCs are carbon-based chemicals that easily evaporate at room temperature, releasing harmful pollutants into the air. These compounds can contribute to indoor air pollution and have been linked to various health issues such as respiratory problems, headaches, and allergic reactions. Therefore, it is important to be aware of the presence of VOCs in these products and opt for low VOC or VOC-free alternatives whenever possible.Rate this question:
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- 3.
The portion of the atmosphere closest to the earth is called the:
- A.
Stratosphere
- B.
Ionosphere
- C.
Mesosphere
- D.
Troposphere
Correct Answer
D. TroposphereExplanation
The troposphere is the layer of the atmosphere closest to the Earth's surface. It extends from the surface up to about 10 kilometers (6.2 miles) in altitude. This is where weather occurs and where most of the Earth's air mass is concentrated. The troposphere is characterized by decreasing temperature with increasing altitude, and it contains the majority of the Earth's clouds and weather systems.Rate this question:
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- 4.
By weight how much of the air is contained in the portion of the atmosphere closest to the earth:
- A.
60%
- B.
75%
- C.
80%
- D.
95%
Correct Answer
D. 95%Explanation
The correct answer is 95% because the portion of the atmosphere closest to the Earth is known as the troposphere, which extends up to about 10-15 kilometers from the surface. This layer contains the majority of the air molecules and is where weather phenomena occur. Since air has weight, the percentage of air in this portion of the atmosphere can be estimated by considering the total weight of the atmosphere. The troposphere contains almost all of the atmosphere's mass, making up about 95% of its total weight.Rate this question:
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- 5.
Which of the following is not a secondary pollutant:
- A.
Nitrates
- B.
Ozone
- C.
SO2
- D.
Sulfates
Correct Answer
C. SO2Explanation
SO2 is not a secondary pollutant because it is directly emitted into the atmosphere from sources such as industrial processes and burning fossil fuels. Secondary pollutants, on the other hand, are formed in the atmosphere through chemical reactions involving primary pollutants. Nitrates, ozone, and sulfates are examples of secondary pollutants that are formed through reactions involving other pollutants like nitrogen oxides, volatile organic compounds, and sulfur dioxide.Rate this question:
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- 6.
Which of the following is not a criteria pollutant:
- A.
Formaldehyde
- B.
Carbon monoxide
- C.
Lead
- D.
Total suspended particulate
- E.
PM-10
Correct Answer
A. FormaldehydeExplanation
Formaldehyde is not considered a criteria pollutant. Criteria pollutants are six common air pollutants regulated by the Environmental Protection Agency (EPA) due to their adverse effects on human health and the environment. These pollutants include carbon monoxide, lead, total suspended particulate matter, and PM-10 (particulate matter with a diameter of 10 micrometers or less). However, formaldehyde is not included in this list. While formaldehyde can be harmful at high concentrations, it is not classified as a criteria pollutant by the EPA.Rate this question:
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- 7.
Carbon monoxide has a 500 times greater affinity to hemoglobin in the blood than oxygen.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Carbon monoxide actually has a 200-250 times greater affinity to hemoglobin in the blood than oxygen. This means that it binds to hemoglobin more readily and strongly than oxygen does, leading to a decreased ability of the blood to carry oxygen to the body's tissues. This is why carbon monoxide poisoning can be so dangerous, as it can quickly replace oxygen in the bloodstream and lead to oxygen deprivation in vital organs. Therefore, the statement that carbon monoxide has a 500 times greater affinity to hemoglobin in the blood than oxygen is false.Rate this question:
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- 8.
Most carbon monoxide deaths are caused by faulty heating systems
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Faulty heating systems can release carbon monoxide, which is a colorless and odorless gas that can be deadly when inhaled. Carbon monoxide poisoning can occur when there is incomplete combustion of fuels such as gas, oil, or coal. Faulty heating systems can produce high levels of carbon monoxide, leading to poisoning and potentially death if not detected and addressed in a timely manner. Therefore, it is true that most carbon monoxide deaths are caused by faulty heating systems.Rate this question:
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- 9.
During high temperature combustion what is the predominant type of NOx that is formed:
- A.
NO2
- B.
N2O5
- C.
NO
- D.
None of the above
Correct Answer
C. NOExplanation
During high temperature combustion, the predominant type of NOx that is formed is NO. This is because the high temperature causes the nitrogen and oxygen molecules in the air to react and form nitrogen monoxide (NO) molecules. NOx refers to a group of nitrogen oxides, but in this specific scenario, NO is the most common type of NOx formed.Rate this question:
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- 10.
Generally the higher the combustion temperature the greater amount of NOx is formed.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
This statement is true because when the combustion temperature is higher, it causes nitrogen and oxygen in the air to react and form nitrogen oxides (NOx). NOx is a harmful pollutant that contributes to air pollution and can have negative effects on human health and the environment. Therefore, it is correct to say that the higher the combustion temperature, the greater amount of NOx is formed.Rate this question:
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- 11.
High Ozone levels typically are experienced during periods of :
- A.
Unstable Low Atmospheric Pressure and high temperatures
- B.
Stable High Atmospheric Pressure and high temperatures
- C.
Turbulent mixing in the atmosphere
- D.
Inversions
Correct Answer
B. Stable High Atmospheric Pressure and high temperaturesExplanation
High ozone levels are typically experienced during periods of stable high atmospheric pressure and high temperatures. During stable high pressure, air is compressed and sinks towards the Earth's surface, preventing vertical mixing of pollutants. This leads to the accumulation of ozone near the surface. Additionally, high temperatures enhance the chemical reactions that produce ozone. Therefore, stable high atmospheric pressure and high temperatures create conditions that favor the formation and accumulation of ozone, resulting in high ozone levels.Rate this question:
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- 12.
What two pollutants are responsible for ozone formation in the lower atmosphere?
- A.
NOx
- B.
SO2
- C.
CO
- D.
VOC
Correct Answer(s)
A. NOx
D. VOCExplanation
NOx (nitrogen oxides) and VOCs (volatile organic compounds) are two pollutants that are responsible for ozone formation in the lower atmosphere. When NOx and VOCs are released into the air, they can react with sunlight to form ground-level ozone. NOx is primarily emitted from vehicles, power plants, and industrial sources, while VOCs can come from various sources such as gasoline, solvents, and certain industrial processes. These pollutants undergo a series of chemical reactions in the presence of sunlight to produce ozone, which can have harmful effects on human health and the environment.Rate this question:
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- 13.
Particulate matter is either a solid or a liquid during standard atmospheric conditions.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Particulate matter refers to tiny particles suspended in the air, such as dust, smoke, and soot. These particles can be either solid or liquid, depending on their composition and size. Under standard atmospheric conditions, which include normal temperature and pressure levels, particulate matter can exist in both solid and liquid forms. Therefore, the statement that particulate matter is either a solid or a liquid during standard atmospheric conditions is true.Rate this question:
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- 14.
PM-10 particles have a settling time of approximately:
- A.
3.6 m/hr
- B.
2.0 m/hr
- C.
0.4 m/hr
- D.
Negligible
Correct Answer
C. 0.4 m/hrExplanation
PM-10 particles have a settling time of approximately 0.4 m/hr. This means that these particles, which have a diameter of 10 micrometers or less, will settle at a rate of 0.4 meters per hour. This settling time indicates the speed at which these particles will fall out of the air and settle onto surfaces. It is important to measure and monitor the settling time of PM-10 particles as they can have harmful effects on human health when inhaled.Rate this question:
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- 15.
From lowest to highest list the following fuels in relationship to their sulfur content:a. Bituminous coalb. No. 2 fuel oilc. No. 6 fuel oild. Natural gase. Antracite coal
- A.
B, c, d, e, a
- B.
D, b, c, e, a
- C.
B, c, d, a, e
- D.
D, b, c, a, e
Correct Answer
B. D, b, c, e, aExplanation
The correct order of fuels from lowest to highest sulfur content is: d (Natural gas), b (No. 2 fuel oil), c (No. 6 fuel oil), e (Antracite coal), a (Bituminous coal).Rate this question:
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- 16.
What gas is most responsible for forming acidic precipitation?
- A.
SO2
- B.
NOx
- C.
CO
- D.
CO2
Correct Answer
A. SO2Explanation
SO2, or sulfur dioxide, is the gas most responsible for forming acidic precipitation. When SO2 is released into the atmosphere from sources such as burning fossil fuels, it reacts with oxygen and other compounds to form sulfuric acid. This sulfuric acid then combines with water vapor in the atmosphere to form sulfuric acid droplets, which are a major component of acid rain. Acidic precipitation can have harmful effects on the environment, including damaging forests, lakes, and buildings.Rate this question:
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- 17.
What is the typical pH of natural rainfall?
- A.
3.5
- B.
5.5
- C.
6.0
- D.
7.5
Correct Answer
B. 5.5Explanation
The typical pH of natural rainfall is 5.5. Rainfall is naturally slightly acidic due to the presence of carbon dioxide in the atmosphere, which forms carbonic acid when dissolved in water. This acidity can vary depending on factors such as pollution and geographical location. A pH of 5.5 indicates a slightly acidic condition, but it is still close to neutral on the pH scale.Rate this question:
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- 18.
The smallest particle size collected at 100% efficiency in a cyclone is known as:
- A.
Cut size
- B.
Geometric size
- C.
Aerodynamic mean size
- D.
Critical size
Correct Answer
D. Critical sizeExplanation
The correct answer is critical size. In a cyclone, the critical size refers to the smallest particle size that can be collected with 100% efficiency. This means that any particles smaller than the critical size will not be collected by the cyclone. The critical size is an important parameter to consider when designing and operating cyclones for particle separation and collection.Rate this question:
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- 19.
The average velocity through a 4ft. X 5ft. diameter rectangular stack is 30 feet / sec. What is the volume in acfm?
- A.
600
- B.
60
- C.
3,600
- D.
36,000
Correct Answer
D. 36,000Explanation
The volume in acfm can be calculated by multiplying the average velocity (30 feet/sec) by the cross-sectional area of the rectangular stack. The cross-sectional area can be found by multiplying the length (4 ft) by the width (5 ft), which equals 20 square feet. Therefore, the volume in acfm is 30 feet/sec * 20 square feet = 600 acfm.Rate this question:
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- 20.
The exhaust from a baghouse stack has a concentration of 0.2 gr./dscf. Given an exhaust of 10,000 scfm what is the emission rate in lbs./hr?
- A.
1.0
- B.
1.7
- C.
3.4
- D.
5.0
Correct Answer
B. 1.7Explanation
The emission rate can be calculated by multiplying the concentration of the exhaust (0.2 gr./dscf) by the flow rate of the exhaust (10,000 scfm) and then converting the units to lbs./hr. Therefore, the emission rate is 1.7 lbs./hr.Rate this question:
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- 21.
How many cylindrical bags, 6 inches in diameter and 25 feet long, would be needed to filter a particulate laden stream? The total filtering surface area is 4045 square feet.
- A.
15
- B.
25
- C.
103
- D.
150
- E.
300
Correct Answer
C. 103Explanation
To find the number of cylindrical bags needed, we need to calculate the total filtering surface area of one bag. The surface area of a cylinder is given by the formula 2πrh + πr^2, where r is the radius and h is the height. In this case, the radius is 3 inches (half of the diameter) and the height is 25 feet. Converting the radius to feet, we get 0.25 feet. Plugging these values into the formula, we get a surface area of approximately 28.27 square feet for one bag. Dividing the total filtering surface area of 4045 square feet by the surface area of one bag, we get approximately 103 bags needed.Rate this question:
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- 22.
What are the two basic mechanisms for particulate collection in a fabric collector:
- A.
Diffusion and precipitation
- B.
Impaction and interception
- C.
Agglomeration and diffusion
- D.
Electrostatic attraction and agglomeration
Correct Answer
B. Impaction and interceptionExplanation
Impaction and interception are the two basic mechanisms for particulate collection in a fabric collector. Impaction occurs when particles collide with the fabric fibers and become trapped due to their inertia. Interception, on the other hand, happens when particles are intercepted by the fabric fibers as they pass through the collector. Both mechanisms play a crucial role in capturing and removing particulate matter from the air, making them essential for effective air pollution control in fabric collectors.Rate this question:
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- 23.
The type of flow in a stack is defined by:
- A.
Avagadros Number
- B.
Atomic number
- C.
Reynolds Number
- D.
Bernoulli's Equation
Correct Answer
C. Reynolds NumberExplanation
The Reynolds number is used to determine the type of flow in a stack. It is a dimensionless quantity that relates the inertial forces to the viscous forces in a fluid flow. It helps to classify flow as laminar or turbulent. Laminar flow occurs at low Reynolds numbers and is characterized by smooth and orderly flow. Turbulent flow occurs at high Reynolds numbers and is characterized by chaotic and irregular flow patterns. Therefore, the Reynolds number is used to define the type of flow in a stack.Rate this question:
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- 24.
A coal fired boiler is controlled by a spray dryer, a baghouse, and SCR. Match the pollutant with the control device used:SOxNOxParticulate
- A.
Particulate - baghouse SOx - spraydryer NOx - SCR
- B.
Particulate - spraydryer NOx - baghouse SOx - SCR
- C.
NOx - SCR SOx - spraydryer Particulate - baghouse
Correct Answer
A. Particulate - baghouse SOx - spraydryer NOx - SCR -
- 25.
The above collectors are arranged in:
- A.
Series
- B.
Parallel
Correct Answer
A. SeriesExplanation
The above collectors are arranged in series. This means that the collectors are connected end to end, with the output of one collector connected to the input of the next collector. In a series arrangement, the total voltage across the collectors is equal to the sum of the individual collector voltages.Rate this question:
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- 26.
In a reverse air baghouse, particulate is collected on:
- A.
The inside of the bag
- B.
The exterior of the bag
Correct Answer
A. The inside of the bagExplanation
In a reverse air baghouse, particulate is collected on the inside of the bag. This means that the bags are designed in such a way that the dirty gas flows from the outside of the bag to the inside. As the gas passes through the bag, the particulate matter is trapped on the inside surface of the bag. This method of collection allows for easier cleaning and maintenance of the baghouse system.Rate this question:
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- 27.
The inlet temperature to a baghouse needs to be above the dewpoint to prevent blinding the bags by condensing moisture in the gas.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
To prevent blinding the bags in a baghouse, the inlet temperature needs to be above the dewpoint. This is because if the temperature of the gas entering the baghouse drops below the dewpoint, moisture in the gas will condense and form droplets. These droplets can then accumulate on the bags, causing them to become clogged or blinded. By maintaining an inlet temperature above the dewpoint, the moisture in the gas remains in a gaseous state and does not condense, preventing blinding of the bags. Therefore, the statement "The inlet temperature to a baghouse needs to be above the dewpoint to prevent blinding the bags by condensing moisture in the gas" is true.Rate this question:
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- 28.
Which of the fabrics listed below would have a good resistence to acid and alkaline attack and also have a high temperature limitation?
- A.
Cotton
- B.
Wool
- C.
Polyester
- D.
Gortex
Correct Answer
C. PolyesterExplanation
Polyester is the correct answer because it has good resistance to acid and alkaline attack. It is a synthetic fabric that is known for its durability and ability to withstand harsh chemicals. Additionally, polyester has a high temperature limitation, meaning it can withstand high heat without melting or deforming. This makes it a suitable choice for applications where resistance to acids, alkalines, and high temperatures is required.Rate this question:
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- 29.
An example of a high energy scrubber would be a:
- A.
Spray tower
- B.
Contact absorber
- C.
Venturi scrubber
- D.
Centrifugal scrubber
Correct Answer
C. Venturi scrubberExplanation
A venturi scrubber is an example of a high energy scrubber because it utilizes a venturi throat to create a high velocity and turbulent gas stream. This high energy gas stream helps in the efficient mixing of the scrubbing liquid with the pollutant particles, resulting in effective particle capture and removal. The venturi scrubber is particularly suitable for applications where the pollutant particles are small and difficult to capture using other scrubbing methods.Rate this question:
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- 30.
Henry's law applies if the equilibrium diagram of a system is a straight line. For most systems, the equilibrium diagram is a straight line if:
- A.
The solution is concentrated
- B.
The solution is dilute
- C.
Water is the solute
- D.
The partial pressure of the absorbate is large
Correct Answer
B. The solution is diluteExplanation
In Henry's law, the equilibrium diagram of a system is a straight line when the solution is dilute. This means that the concentration of the solute in the solution is relatively low. In dilute solutions, the solute particles are dispersed and do not interact strongly with each other. As a result, the relationship between the concentration of the solute and its partial pressure in the gas phase is linear. In contrast, in concentrated solutions, the solute particles are closer together and may interact more strongly, leading to deviations from linearity in the equilibrium diagram. Therefore, the correct answer is that the solution is dilute.Rate this question:
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- 31.
In air pollution applications, chemical adsorption is preferable to physical adsorption.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Chemical adsorption is not preferable to physical adsorption in air pollution applications. Physical adsorption involves the physical attraction of pollutants to a solid surface, while chemical adsorption involves the formation of chemical bonds between the pollutants and the adsorbent material. In air pollution applications, physical adsorption is generally preferred because it is more reversible and allows for easier regeneration of the adsorbent material. Chemical adsorption, on the other hand, is more difficult to reverse and requires more energy-intensive processes for regeneration. Therefore, the statement is false.Rate this question:
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- 32.
The exhaust from a boiler has a CO concentration with a partial pressure of 19.0 mm HG. Given a standard pressure of 760 mm HG what is the ppm of CO in exhaust?
- A.
2,500
- B.
5,000
- C.
25,000
- D.
50,000
Correct Answer
C. 25,000Explanation
The partial pressure of CO in the exhaust is given as 19.0 mm Hg. To find the ppm (parts per million) of CO, we need to compare this partial pressure to the standard pressure of 760 mm Hg.
To do this, we can use the equation:
ppm = (partial pressure of CO / standard pressure) * 1,000,000
Substituting the given values, we get:
ppm = (19.0 mm Hg / 760 mm Hg) * 1,000,000
Simplifying this equation gives us:
ppm = 25,000
Therefore, the ppm of CO in the exhaust is 25,000.Rate this question:
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- 33.
What is a flue gas treatement process that can be used to reduce NOx in a combustion unit:
- A.
Electrostatic precipitation
- B.
Selective catalytic reduction
- C.
Limestone injections
- D.
Carbon injections
Correct Answer
B. Selective catalytic reductionExplanation
Selective catalytic reduction (SCR) is a flue gas treatment process that can be used to reduce NOx (nitrogen oxides) in a combustion unit. It involves the injection of a reductant, such as ammonia or urea, into the flue gas stream. The flue gas containing NOx is then passed over a catalyst, where a chemical reaction occurs between the NOx and the reductant. This reaction converts the NOx into nitrogen and water vapor, reducing the emissions of harmful pollutants. SCR is a widely used and effective method for reducing NOx emissions in industrial processes and power plants.Rate this question:
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- 34.
What formula represents the ideal gas law?
- A.
PV=nRT
- B.
PVM = RTstd
- C.
V = TP
- D.
PV = MwRT
Correct Answer
A. PV=nRTExplanation
The ideal gas law is represented by the formula PV=nRT. This formula states that the pressure (P) multiplied by the volume (V) of a gas is equal to the number of moles (n) of the gas multiplied by the ideal gas constant (R) and the temperature (T) in Kelvin. This equation is used to describe the behavior of an ideal gas under various conditions, allowing for calculations of pressure, volume, temperature, and number of moles.Rate this question:
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- 35.
If a certified Method 9 observer reads 75% opacity, how much light transmission can be seen through the plume?
- A.
10%
- B.
25%
- C.
50%
- D.
75%
Correct Answer
B. 25%Explanation
If a certified Method 9 observer reads 75% opacity, it means that 75% of the light is blocked or obscured by the plume. Therefore, only 25% of the light transmission can be seen through the plume.Rate this question:
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- 36.
The Discharge Electrode in an Electrostatic Precipitator is usually:
- A.
Neutrally charged
- B.
Positively charged
- C.
Negatively charged
Correct Answer
C. Negatively chargedExplanation
The Discharge Electrode in an Electrostatic Precipitator is usually negatively charged. This is because the discharge electrode is responsible for generating a corona discharge, which creates a strong electric field. This electric field attracts and ionizes the particles present in the gas stream, causing them to become charged. The negatively charged discharge electrode helps to attract and collect the positively charged particles, allowing for efficient particle removal in the electrostatic precipitator.Rate this question:
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- 37.
An inversion condition exists when you have:
- A.
Cool air above warm air
- B.
No wind
- C.
Cumulus clouds
- D.
Warm air above cool air
Correct Answer
D. Warm air above cool airExplanation
The given answer suggests that an inversion condition exists when warm air is present above cool air. This is because in a normal atmosphere, temperature decreases with increasing altitude. However, during an inversion, a layer of warm air traps cool air beneath it, preventing it from rising. This can lead to stable atmospheric conditions with little to no vertical mixing, resulting in the absence of wind and the formation of cumulus clouds.Rate this question:
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- 38.
In the absorption process you have the transfer of a gaseous component from the gas phase to the liquid phase.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The absorption process refers to the transfer of a gaseous component from the gas phase to the liquid phase. This means that the gas is being taken in or dissolved by the liquid. Therefore, the given statement is true.Rate this question:
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- 39.
In an absorber, if the temperature of the liquid increases the solubility of the gaseous component into the liquid normally:
- A.
Stays the same
- B.
Increases
- C.
Decreases
Correct Answer
C. DecreasesExplanation
When the temperature of a liquid in an absorber increases, the solubility of the gaseous component into the liquid decreases. This is because an increase in temperature generally leads to an increase in kinetic energy of the molecules, causing them to move faster and creating more space between them. As a result, the liquid molecules are less likely to interact and bond with the gaseous molecules, leading to a decrease in solubility.Rate this question:
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- 40.
The attractive forces that hold a gas to the surface of a solid are known as:
- A.
Negatively charged forces
- B.
Van der Waals Forces
- C.
Positively charged forces
- D.
Henry's Law Force
Correct Answer
B. Van der Waals ForcesExplanation
Van der Waals forces are the attractive forces that hold a gas to the surface of a solid. These forces arise due to temporary fluctuations in electron distribution within molecules, resulting in temporary dipoles. These temporary dipoles induce opposite charges in neighboring molecules, creating attractive forces between them. Van der Waals forces are relatively weak compared to other types of chemical bonds, but they play a significant role in various phenomena, such as the condensation of gases into liquids and the adsorption of gases onto solid surfaces.Rate this question:
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- 41.
The principal commercial adsorbent used for the adsorption of organic vapors is:
- A.
Silica gel
- B.
Carbon
- C.
Alumina
- D.
Stainless steel mesh
- E.
Zeolite
Correct Answer
B. CarbonExplanation
Carbon is the principal commercial adsorbent used for the adsorption of organic vapors because it has a high surface area and can effectively adsorb a wide range of organic compounds. It is a highly porous material with a large number of micropores, which provide a large surface area for adsorption. Carbon also has a high adsorption capacity and can remove organic contaminants from air or liquids. Additionally, carbon is cost-effective, readily available, and can be regenerated for reuse, making it a preferred choice for commercial adsorption applications.Rate this question:
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- 42.
A packed countercurrent flow absorber is more efficient than a spray tower because:
- A.
The pressure drop increases
- B.
The tank diameter is usually larger
- C.
The tower height is increased
- D.
The gas-liquid interfacial area is increased
Correct Answer
D. The gas-liquid interfacial area is increasedExplanation
In a packed countercurrent flow absorber, the gas and liquid flow in opposite directions, allowing for a greater contact area between them. This increases the gas-liquid interfacial area, which enhances the mass transfer between the two phases and improves the efficiency of the absorber. The other options mentioned, such as increased pressure drop, larger tank diameter, and increased tower height, do not directly contribute to the efficiency of the absorber in the same way as increasing the gas-liquid interfacial area.Rate this question:
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- 43.
A condenser is not an effective way to control alcohol vapors.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
A condenser is an effective way to control alcohol vapors. A condenser is a device that cools down and condenses vapors into a liquid form. In the context of controlling alcohol vapors, a condenser can be used to capture and collect the alcohol vapors, preventing them from escaping into the environment. This is commonly used in distillation processes, where alcohol vapors are condensed and collected to produce alcoholic beverages or other products. Therefore, the statement "A condenser is not an effective way to control alcohol vapors" is false.Rate this question:
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- 44.
Which of the following oxidizers would be the most cost effective?
- A.
Thermal oxidizer
- B.
Regenerative thermal oxidizer
- C.
Catalytic oxidizer
Correct Answer
C. Catalytic oxidizerExplanation
A catalytic oxidizer would be the most cost-effective option among the given choices. This is because a catalytic oxidizer utilizes a catalyst to promote the oxidation of pollutants at lower temperatures, resulting in reduced fuel consumption and operating costs. It offers higher energy efficiency and lower operating expenses compared to a thermal oxidizer or a regenerative thermal oxidizer, making it a more cost-effective solution for air pollution control.Rate this question:
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- 45.
In the combustion process, if you need two moles of oxygen to combust one mole of methane, how many moles of air would be needed?
- A.
2
- B.
3.99
- C.
7.53
- D.
9.53
- E.
13.28
Correct Answer
D. 9.53Explanation
In the combustion process, methane (CH4) reacts with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O). The balanced chemical equation for this reaction is:
CH4 + 2O2 -> CO2 + 2H2O
From the equation, we can see that 1 mole of methane requires 2 moles of oxygen. Since air is approximately 21% oxygen, the rest being mostly nitrogen, we need to calculate how many moles of air would contain 2 moles of oxygen.
To do this, we divide 2 moles of oxygen by the mole fraction of oxygen in air (0.21):
2 moles O2 / 0.21 = 9.52 moles of air
Therefore, the correct answer is 9.53 moles.Rate this question:
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- 46.
NOx control is usually accomplished through what process?
- A.
Absorption
- B.
Reduction
- C.
Oxidation
- D.
Adsorption
Correct Answer
B. ReductionExplanation
NOx control is usually accomplished through the reduction process. Reduction involves converting nitrogen oxides (NOx) into harmless nitrogen (N2) and water (H2O) by introducing a reducing agent, such as ammonia or urea, into the exhaust gases. This process breaks down the nitrogen oxides and transforms them into less harmful substances, reducing their environmental impact.Rate this question:
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- 47.
In the combustion of natural gas, most of the NOx produced is considered:
- A.
Fuel NOx
- B.
Thermal NOx
- C.
Residual NOx
Correct Answer
B. Thermal NOxExplanation
In the combustion of natural gas, the majority of the NOx produced is considered to be Thermal NOx. This type of NOx is formed when nitrogen and oxygen in the air react at high temperatures, such as those found in the combustion process. The heat causes nitrogen and oxygen molecules to combine and form NOx compounds. This is different from Fuel NOx, which is formed when the nitrogen in the fuel itself reacts with oxygen, and Residual NOx, which is formed from impurities in the fuel.Rate this question:
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- 48.
Which of the following fuels would have the highest nitrogen content:
- A.
Natural gas
- B.
No. 2 oil
- C.
No. 6 oil
- D.
Coal
Correct Answer
D. CoalExplanation
Coal would have the highest nitrogen content among the given options. Coal is a fossil fuel that is formed from the remains of plants and trees over millions of years. It contains a significant amount of nitrogen, which is released as nitrogen oxides (NOx) when coal is burned. This makes coal a major contributor to air pollution and a significant source of nitrogen emissions. Natural gas, No. 2 oil, and No. 6 oil have lower nitrogen content compared to coal.Rate this question:
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- 49.
Bituminous coal fired utilities usually use what process to control SO2?
- A.
Limestone process
- B.
Dry scrubbing
- C.
Magnesium oxide process
- D.
Dry injection
Correct Answer
A. Limestone processExplanation
Bituminous coal fired utilities usually use the limestone process to control SO2. This process involves injecting limestone into the flue gas stream, where it reacts with the sulfur dioxide to form calcium sulfite. This calcium sulfite can then be further oxidized to form calcium sulfate, which is a solid waste product. The limestone process is a commonly used method for reducing SO2 emissions in coal-fired power plants, as it is effective and relatively cost-efficient.Rate this question:
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- 50.
Emission inventories are usually required for all stationary sources regardless of their size.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Emission inventories are not usually required for all stationary sources regardless of their size. The requirement for emission inventories typically depends on the regulations and policies set by the governing authorities. While larger stationary sources are often required to report their emissions, smaller sources may be exempt from this requirement. Therefore, the statement that emission inventories are required for all stationary sources regardless of their size is false.Rate this question:
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Mar 22, 2023Quiz Edited by
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Sep 17, 2009Quiz Created by
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