3e151 CDC Set C/P Volume 3
- 1.
Which water source is generally clear, cool, low in organic material, and frequently hard?
- A.
Lake.
- B.
Pond.
- C.
Spring.
- D.
Stream.
Correct Answer
C. Spring.Explanation
A spring is generally a water source that is clear, cool, low in organic material, and frequently hard. Springs are formed when groundwater emerges naturally from the ground, often from underground aquifers. The water in springs is usually clear because it has been filtered through layers of soil and rocks. It is also cool because it comes from deep underground where temperatures are lower. Springs are typically low in organic material because the water has not been exposed to surface contaminants. Lastly, springs often have high mineral content, making them hard water sources.Rate this question:
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- 2.
A lake surface water source, with considerable self-purification, is similar to which othertype of surface water source?
- A.
Pond
- B.
Spring
- C.
Ground
- D.
Stream
Correct Answer
D. StreamExplanation
A lake surface water source, with considerable self-purification, is similar to a stream. Both streams and lakes have flowing water, which helps in the natural purification process by diluting pollutants and carrying them away. Additionally, both types of water sources support aquatic life and provide habitat for various organisms.Rate this question:
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- 3.
Suspended matter of any nature present in water is
- A.
Hardness
- B.
Turbidity
- C.
Organic matter
- D.
Dissolved solids
Correct Answer
B. TurbidityExplanation
Turbidity refers to the cloudiness or haziness of water caused by suspended particles such as sediment, algae, or other organic and inorganic matter. It is a measure of the water's clarity and can affect its appearance and quality. Therefore, the correct answer for the given question is turbidity.Rate this question:
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- 4.
Which impurity is used to determine the cycles of concentration (COC)?
- A.
Free mineral acids
- B.
Carbon dioxide
- C.
Turbidity
- D.
Chloride
Correct Answer
D. ChlorideExplanation
Chloride is used to determine the cycles of concentration (COC). The presence of chloride impurities in water can lead to corrosion in industrial equipment. By measuring the chloride levels, one can determine the COC, which is the ratio of the concentration of impurities in the makeup water to the concentration of impurities in the blowdown water. This helps in monitoring and controlling the water treatment process to prevent excessive impurity buildup and potential equipment damage.Rate this question:
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- 5.
The presence of hydrogen ions causes a solution to be
- A.
Turbid
- B.
Acidic
- C.
Neutral
- D.
Alkaline
Correct Answer
B. AcidicExplanation
When hydrogen ions are present in a solution, it means that the solution has a high concentration of H+ ions. This high concentration of H+ ions indicates that the solution is acidic. Acidity is a property of a solution that is determined by the concentration of hydrogen ions present in it. Therefore, the correct answer is acidic.Rate this question:
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- 6.
A pH of 5 in a water system, such as a boiler, aids in the development of
- A.
Foam
- B.
Scale
- C.
Corrosion
- D.
Hydroxides
Correct Answer
C. CorrosionExplanation
A pH of 5 in a water system, such as a boiler, aids in the development of corrosion. This is because a pH of 5 indicates an acidic environment, which can cause the breakdown of metal surfaces and lead to corrosion. Acidic conditions can react with the metal components in the water system, causing them to deteriorate over time. Therefore, a pH of 5 in a water system is likely to promote corrosion.Rate this question:
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- 7.
Which items has no bearing on the formation of scale?
- A.
Iron
- B.
Hardness
- C.
Alkalinity
- D.
Temperature
Correct Answer
A. IronExplanation
Iron does not have any bearing on the formation of scale. Scale is typically formed by the precipitation of minerals, such as calcium and magnesium, from hard water. Iron, on the other hand, can contribute to the formation of rust or iron deposits, but it does not directly contribute to the formation of scale.Rate this question:
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- 8.
Which of the types of alkalinity will not cause scale?
- A.
Ionic alkalinity
- B.
Carbonate alkalinity
- C.
Hydroxide alkalinity
- D.
Bicarbonate alkalinity
Correct Answer
C. Hydroxide alkalinityExplanation
Hydroxide alkalinity will not cause scale because it is not associated with the formation of mineral deposits. Scale formation occurs when certain minerals, such as calcium and magnesium, precipitate out of solution and form solid deposits. Carbonate alkalinity and bicarbonate alkalinity can contribute to scale formation, as they are often associated with the presence of these minerals. Ionic alkalinity is a broad term that encompasses all types of alkalinity, so it is not specific enough to determine whether it will cause scale or not. However, hydroxide alkalinity specifically does not contribute to scale formation.Rate this question:
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- 9.
Corrosion caused by acid produced by carbon dioxide usually shows up as
- A.
Pitting along the bottom of the piping
- B.
Grooves along the bottom of the piping
- C.
Pitting on the entire surface of the piping
- D.
Grooves on the entire surface of the piping
Correct Answer
B. Grooves along the bottom of the pipingExplanation
Corrosion caused by acid produced by carbon dioxide usually shows up as grooves along the bottom of the piping. This is because carbon dioxide can react with water to form carbonic acid, which can corrode the metal surface of the piping. The acid tends to concentrate at the bottom of the piping due to gravity, leading to the formation of grooves along that area.Rate this question:
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- 10.
The clarification process is used to remove
- A.
All silica from feedwater.
- B.
Calcium and magnesium.
- C.
Suspended impurities.
- D.
Dissolved solids.
Correct Answer
C. Suspended impurities.Explanation
The clarification process is used to remove suspended impurities from feedwater. Suspended impurities refer to solid particles or substances that are suspended in the water and can be seen with the naked eye or through turbidity. These impurities can include dirt, sand, clay, algae, and other organic or inorganic particles. The clarification process involves techniques such as sedimentation, coagulation, and filtration to separate and remove these suspended impurities, resulting in clearer and cleaner water.Rate this question:
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- 11.
The process of chemically separating one substance out in solid form from a solutiondescribes what water treatment process?
- A.
Filtration
- B.
Clarification
- C.
Sedimentation
- D.
Chemical precipitation
Correct Answer
D. Chemical precipitationExplanation
Chemical precipitation is the process of chemically separating one substance out in solid form from a solution. In water treatment, chemical precipitation is used to remove contaminants from water by adding chemicals that react with the contaminants to form insoluble particles. These particles then settle out of the water, allowing for their removal through sedimentation or filtration. This process is commonly used to remove heavy metals, such as lead or mercury, from water sources.Rate this question:
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- 12.
Which external water softening treatment process relies on a temperature of 212° F toremove hardness from system water?
- A.
Cold lime soda
- B.
Hot lime soda
- C.
Sodium zeolite water
- D.
Hydrogen zeolite water
Correct Answer
B. Hot lime sodaExplanation
Hot lime soda is an external water softening treatment process that relies on a temperature of 212°F to remove hardness from system water. In this process, lime and soda ash are added to the water at high temperatures, causing the hardness minerals to precipitate out. The high temperature helps to accelerate the chemical reactions and improve the efficiency of the softening process. This method is commonly used in industrial settings where large quantities of water need to be softened.Rate this question:
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- 13.
What external water softening treatment process uses acid to help remove hardness fromwater?
- A.
Hot lime soda
- B.
Cold lime soda
- C.
Sodium Zeolite
- D.
Hydrogen Zeolite
Correct Answer
D. Hydrogen ZeoliteExplanation
Hydrogen Zeolite is an external water softening treatment process that uses acid to help remove hardness from water. Zeolite is a mineral that has a high affinity for calcium and magnesium ions, which are the main causes of water hardness. When water passes through a bed of hydrogen zeolite, the calcium and magnesium ions in the water are exchanged with hydrogen ions on the zeolite. This process effectively removes the hardness from the water, making it soft. The use of acid in this process helps regenerate the zeolite bed by removing the accumulated hardness ions and restoring its capacity to soften water.Rate this question:
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- 14.
During the external treatment of water to be used in a mechanical system, aeration is used to
- A.
Increase the CO2 level
- B.
Remove the CO2 level
- C.
Increase the CO level
- D.
Remove the CO level
Correct Answer
B. Remove the CO2 levelExplanation
Aeration is the process of introducing air into water. When water is aerated, it allows for the release of dissolved gases, including carbon dioxide (CO2). Therefore, aeration is used to remove the CO2 level from the water during the external treatment process.Rate this question:
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- 15.
How much of the initial free oxygen can be removed by heating the boiler feedwater to thesaturation temperature?
- A.
80 to 85 percent
- B.
85 to 90 percent
- C.
90 to 95 percent
- D.
95 to 100 percent
Correct Answer
C. 90 to 95 percentExplanation
Heating the boiler feedwater to the saturation temperature can remove 90 to 95 percent of the initial free oxygen. This is because heating the water increases its temperature and reduces the solubility of oxygen in water. As a result, a significant portion of the dissolved oxygen is released as gas, leading to its removal from the feedwater.Rate this question:
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- 16.
Which test should you use to make sure proper regeneration solution of the sodium zeolitesoftener?
- A.
Total hardness
- B.
Dissolved iron
- C.
Diluted acid
- D.
Brine
Correct Answer
D. BrineExplanation
Brine should be used to ensure proper regeneration of the sodium zeolite softener. Brine, which is a highly concentrated salt solution, is commonly used in water softeners to regenerate the resin beads in the softener tank. During the regeneration process, the brine solution is flushed through the resin bed, effectively replacing the hardness ions that have been removed from the water. This allows the resin beads to continue softening the water effectively. Therefore, using brine is essential for maintaining the efficiency and effectiveness of a sodium zeolite softener.Rate this question:
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- 17.
In a cooling system, what is necessary for algae to grow?
- A.
Water, heat, and air
- B.
Air, light, and water
- C.
Heat, light, and water
- D.
Air, light, and minerals
Correct Answer
B. Air, light, and waterExplanation
Algae are photosynthetic organisms that require light for photosynthesis, air for gas exchange, and water for their growth and survival. Without light, algae cannot produce energy through photosynthesis. Without air, they cannot obtain the necessary carbon dioxide for photosynthesis and release oxygen. Without water, algae cannot carry out various metabolic processes and absorb nutrients. Therefore, for algae to grow in a cooling system, all three components - air, light, and water - are necessary.Rate this question:
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- 18.
Crevice corrosion occurs when a solution contains varying amounts of dissolved
- A.
Magnesium
- B.
Oxygen
- C.
Nitrogen
- D.
Calcium
Correct Answer
B. OxygenExplanation
Crevice corrosion is a type of localized corrosion that occurs in narrow gaps or crevices where oxygen supply is limited. Oxygen plays a crucial role in the corrosion process as it acts as an electron acceptor, facilitating the corrosion reaction. In the absence of sufficient oxygen, corrosion is accelerated within the crevice due to the formation of concentration cells and the buildup of aggressive species. Therefore, the presence of oxygen is necessary for crevice corrosion to occur.Rate this question:
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- 19.
What item is particularly useful in monitoring the effectiveness of a chemical corrosioncontrol program?
- A.
Corrosion test coupon
- B.
Corrosion cell
- C.
Electrolytes
- D.
COC
Correct Answer
A. Corrosion test couponExplanation
A corrosion test coupon is a small metal sample that is exposed to the same conditions as the equipment or structure being protected against corrosion. By monitoring the condition of the coupon over time, it is possible to assess the effectiveness of the chemical corrosion control program. If the coupon shows signs of corrosion, it indicates that the program may not be working effectively and adjustments may need to be made. Therefore, a corrosion test coupon is particularly useful in monitoring the effectiveness of a chemical corrosion control program.Rate this question:
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- 20.
The alkalinity level of the water in a steam boiler is monitored closely to prevent
- A.
Acidic corrosion
- B.
The formation of scale
- C.
Caustic boiler seam cracks
- D.
Low levels of sludge formation
Correct Answer
C. Caustic boiler seam cracksExplanation
The alkalinity level of the water in a steam boiler is monitored closely to prevent caustic boiler seam cracks. When the alkalinity level is too high, it can lead to caustic embrittlement, which weakens the boiler seams and increases the risk of cracks. This can be a serious safety hazard as it can result in leaks or even catastrophic failure of the boiler. Therefore, monitoring and maintaining the alkalinity level within the recommended range is essential to prevent caustic boiler seam cracks.Rate this question:
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- 21.
What type carryover is caused by high concentrations of alkalinity, dissolved solids, orsuspended solids?
- A.
Mist
- B.
Silica
- C.
Priming
- D.
Foaming
Correct Answer
D. FoamingExplanation
High concentrations of alkalinity, dissolved solids, or suspended solids can cause foaming. Foaming occurs when these substances create a layer of bubbles on the surface of a liquid. This can be problematic in various industrial processes, such as water treatment or manufacturing, as it can interfere with the efficiency of equipment and cause operational issues. Therefore, foaming is the type of carryover that is caused by high concentrations of alkalinity, dissolved solids, or suspended solids.Rate this question:
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- 22.
When are water samples drawn from an operating boiler?
- A.
As soon as possible after bottom blowdown.
- B.
As soon as possible after adding chemicals.
- C.
Before firing the boiler for the first time.
- D.
Before chemicals are added or before regular blow down is accomplished.
Correct Answer
D. Before chemicals are added or before regular blow down is accomplished.Explanation
Water samples should be drawn from an operating boiler before chemicals are added or before regular blow down is accomplished. This is important because it allows for the analysis of the water quality before any chemical treatment or blow down process takes place. By taking samples at this stage, any potential issues or imbalances in the water chemistry can be identified and addressed before they cause any damage or problems in the boiler system.Rate this question:
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- 23.
The solenoid valve on the blowdown line of a cooling tower is energized when the
- A.
PH reaches 5.0
- B.
PH reaches 9.0
- C.
Water's conductivity exceeds the meter setting
- D.
Water's conductivity drops below the meter setting
Correct Answer
C. Water's conductivity exceeds the meter settingExplanation
The solenoid valve on the blowdown line of a cooling tower is energized when the water's conductivity exceeds the meter setting. This means that when the conductivity of the water being discharged from the cooling tower rises above a certain threshold, the solenoid valve is activated. This is likely done to prevent the discharge of water that is too conductive, which could indicate a high concentration of dissolved solids or contaminants. By activating the solenoid valve, the system can ensure that only water with an acceptable level of conductivity is released.Rate this question:
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- 24.
Who on the base must approve the use of a new chemical or the disposal of waste water?
- A.
Base civil engineer and shop supervisor.
- B.
Base commander and base civil engineer.
- C.
Bioenvironmental engineer and base commander.
- D.
Environmental engineer and bioenvironmental engineer.
Correct Answer
D. Environmental engineer and bioenvironmental engineer.Explanation
The environmental engineer and bioenvironmental engineer are responsible for approving the use of a new chemical or the disposal of waste water on the base. These professionals have the expertise and knowledge to assess the potential environmental impact and ensure that all necessary regulations and protocols are followed. The base commander, base civil engineer, and shop supervisor may have other responsibilities but do not have the specific expertise in environmental matters to make these approvals.Rate this question:
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- 25.
What type solution is used to boil out a new boiler?
- A.
An acidic solution
- B.
An alkaline solution
- C.
A strong soap solution
- D.
A distilled water solution
Correct Answer
B. An alkaline solutionExplanation
An alkaline solution is used to boil out a new boiler. This is because an alkaline solution helps to remove oils, grease, and other contaminants that may be present in the boiler. It also helps to neutralize any acidic substances that may have been used during the manufacturing process. By using an alkaline solution, the boiler can be thoroughly cleaned and prepared for use, ensuring optimal performance and longevity.Rate this question:
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- 26.
Which type of cleaning has replaced mechanical cleaning of process equipment?
- A.
Abrasive blasting
- B.
Wire brushing
- C.
Chemical
- D.
Scraping
Correct Answer
C. ChemicalExplanation
Chemical cleaning has replaced mechanical cleaning of process equipment because it is more effective in removing stubborn dirt, grease, and other contaminants. Chemical cleaning involves the use of specific chemicals that can dissolve or break down these substances, making it easier to clean the equipment. It is also less labor-intensive and time-consuming compared to mechanical cleaning methods such as abrasive blasting, wire brushing, or scraping. Chemical cleaning ensures a thorough and efficient cleaning process, leading to improved equipment performance and productivity.Rate this question:
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- 27.
The best and cheapest pH control program for cooling towers is
- A.
To add lignosulfonate.
- B.
The addition of sulfuric acid.
- C.
Frequent hard bottom blowdowns.
- D.
The constant skimming of the reservoir.
Correct Answer
B. The addition of sulfuric acid.Explanation
Sulfuric acid is the best and cheapest pH control program for cooling towers because it is an effective acid that can lower the pH level quickly and efficiently. It is also cost-effective compared to other pH control methods. By adding sulfuric acid, the acidity of the water increases, which helps prevent the growth of bacteria and algae in the cooling tower. This helps maintain the desired pH level and prevents scaling and corrosion.Rate this question:
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- 28.
When a steam boiler is being treated, what is the principal variable that causes changes inthe chemical dosages?
- A.
Changing operating conditions.
- B.
The percent of condensate being returned.
- C.
The amount of makeup water added.
- D.
Seasonal changes in chemical content.
Correct Answer
C. The amount of makeup water added.Explanation
The amount of makeup water added is the principal variable that causes changes in the chemical dosages when treating a steam boiler. As makeup water is added, it dilutes the existing chemicals in the boiler, requiring adjustments in the dosages to maintain the desired chemical levels. Therefore, the amount of makeup water directly affects the chemical dosages in the boiler treatment process.Rate this question:
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- 29.
Use amines in a steam boiler to
- A.
Precipitate magnesium salts.
- B.
Condition sludge in the boiler.
- C.
Neutralize sulfuric acid in the condensate lines.
- D.
Neutralize carbonic acid in the condensate lines.
Correct Answer
D. Neutralize carbonic acid in the condensate lines.Explanation
Amines are used in a steam boiler to neutralize carbonic acid in the condensate lines. Carbonic acid is formed when carbon dioxide dissolves in water, and it can cause corrosion in the condensate lines. Amines, being basic compounds, react with carbonic acid to form stable salts, effectively neutralizing it and preventing corrosion. This helps to maintain the integrity of the condensate lines and prolong the lifespan of the boiler system.Rate this question:
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- 30.
When adding sodium nitrite is being added to a hot or chilled water system for corrosioncontrol, the desired pH for proper filming is
- A.
6.5-7.5
- B.
7.5-8.5
- C.
8.5-9.5
- D.
9.5-10.5
Correct Answer
D. 9.5-10.5Explanation
When adding sodium nitrite to a hot or chilled water system for corrosion control, the desired pH for proper filming is 9.5-10.5. This pH range is necessary to ensure that a protective film is formed on the metal surfaces, which helps prevent corrosion. A pH below 9.5 may not provide adequate protection, while a pH above 10.5 could lead to other issues such as scale formation. Therefore, maintaining a pH between 9.5 and 10.5 is crucial for effective corrosion control in the water system.Rate this question:
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- 31.
The chemical feeding pump best suited for service when you wish to pump very strongcorrosive chemicals is the
- A.
Gear
- B.
Piston
- C.
Diaphragm
- D.
Reciprocating
Correct Answer
C. DiapHragmExplanation
The diaphragm pump is best suited for pumping very strong corrosive chemicals because it has a flexible diaphragm that separates the chemicals from the pumping mechanism. This diaphragm acts as a barrier, preventing the corrosive chemicals from coming into contact with the pump's internal components, which helps to minimize damage and ensure the longevity of the pump. Additionally, diaphragm pumps are known for their ability to handle high pressures and provide a smooth, consistent flow, making them ideal for pumping corrosive chemicals safely and efficiently.Rate this question:
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- 32.
An antisiphon valve is used on a chemical feed system when the chemical feed tank is
- A.
Above the treated equipment
- B.
Below the treated equipment
- C.
Level the treated equipment
- D.
Beside the treated equipment
Correct Answer
A. Above the treated equipmentExplanation
An antisiphon valve is used on a chemical feed system when the chemical feed tank is above the treated equipment. This is because an antisiphon valve is designed to prevent the backflow of chemicals from the tank into the equipment. By placing the tank above the equipment, gravity can be used to ensure a continuous flow of chemicals without the risk of backflow. This arrangement also helps to maintain the desired pressure and flow rate, ensuring efficient and effective chemical treatment.Rate this question:
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- 33.
Which chemical feed system should you use when you wish to maintain a chemical levelwith very little fluctuation?
- A.
Intermittent
- B.
Continuous
- C.
Shock
- D.
Slug
Correct Answer
B. ContinuousExplanation
When you wish to maintain a chemical level with very little fluctuation, the best chemical feed system to use is a continuous system. This system ensures a steady and constant supply of chemicals, preventing any significant fluctuations in the chemical level. Unlike intermittent, shock, or slug systems, which involve periodic or sudden releases of chemicals, a continuous system provides a consistent and stable chemical supply, making it ideal for maintaining a steady chemical level.Rate this question:
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- 34.
In which methods of chemical feeding do you add a high level of chemicals on aninfrequent basis to provide the necessary “kill” effect?
- A.
Slug
- B.
Shock
- C.
Continuous
- D.
Intermittent
Correct Answer
B. ShockExplanation
In chemical feeding, the method of shock involves adding a high level of chemicals on an infrequent basis to achieve a strong "kill" effect. This method is typically used when there is a sudden increase in the demand for chemicals, such as in the case of a heavy contamination or a sudden outbreak of pathogens. By adding a large dose of chemicals at once, the shock method ensures that the necessary kill effect is achieved quickly and effectively.Rate this question:
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- 35.
When troubleshooting a diaphragm chemical pump, you notice air in the discharge hose andsuspect the valve seal rings are loose. What action should you take?
- A.
Replace the pump, the seals cannot be repaired.
- B.
Replace the pump body, using the old valve and seals.
- C.
Tighten the fittings by hand until very snug, replace the seal rings if it still leaks.
- D.
Tighten the fittings to 24 foot pounds of torque, replace the seal rings if it still leaks.
Correct Answer
C. Tighten the fittings by hand until very snug, replace the seal rings if it still leaks.Explanation
The correct action to take when troubleshooting a diaphragm chemical pump and suspecting loose valve seal rings is to tighten the fittings by hand until very snug and replace the seal rings if it still leaks. This is because loose valve seal rings can cause air to enter the discharge hose, and tightening the fittings can help secure them in place. If the leakage issue persists even after tightening, replacing the seal rings is recommended to ensure proper sealing and prevent further air ingress.Rate this question:
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- 36.
What problem could result from your chemical pump’s feeding into the suction side of asystem recirculating pump?
- A.
Excessive back-pressure causing high feed rates.
- B.
Low back-pressure causing low feed rates.
- C.
A siphoning effect causing excessive output.
- D.
A siphoning effect causing low pump output.
Correct Answer
C. A sipHoning effect causing excessive output.Explanation
Feeding the chemical pump into the suction side of a system recirculating pump can create a siphoning effect, where the chemical pump continuously draws in and pumps out the liquid. This can lead to excessive output of the chemical, which can be problematic and potentially dangerous.Rate this question:
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- 37.
What is the result if the length of the stroke is increased on a piston type chemical pump?
- A.
Frequency of the stroke increases.
- B.
Frequency of the stroke decreases.
- C.
Amount of chemical pumped decreases.
- D.
Amount of chemical pumped increases.
Correct Answer
D. Amount of chemical pumped increases.Explanation
Increasing the length of the stroke on a piston type chemical pump will result in an increased amount of chemical being pumped. This is because a longer stroke allows the piston to displace a larger volume of fluid with each stroke, leading to a higher flow rate and increased amount of chemical being pumped.Rate this question:
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- 38.
When using a bypass feeder and special chemical briquettes, how do you adjust thechemical feed rate?
- A.
Adjusting the regulating valve.
- B.
Adjusting the length of the stroke on the pump.
- C.
Adjusting the frequency of the stroke on the pump.
- D.
Raising or lowering the chemical concentration level.
Correct Answer
A. Adjusting the regulating valve.Explanation
The correct answer is adjusting the regulating valve. When using a bypass feeder and special chemical briquettes, the regulating valve controls the flow of the chemical into the system. By adjusting the regulating valve, the chemical feed rate can be increased or decreased, allowing for precise control of the chemical concentration in the system. This ensures that the correct amount of chemical is being added to the water to effectively treat it.Rate this question:
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- 39.
Which type of chemical feed control uses a special water meter to trigger its operation?
- A.
Pump setting.
- B.
Bypass feeder adjustment.
- C.
Time clock pump setting.
- D.
Flow proportioning control.
Correct Answer
D. Flow proportioning control.Explanation
Flow proportioning control uses a special water meter to trigger its operation. This type of chemical feed control system ensures that the correct amount of chemicals is added to the water based on the flow rate. The water meter measures the flow rate, and the control system adjusts the chemical feed accordingly, maintaining the desired proportion of chemicals to water. This method is efficient and accurate, ensuring precise chemical dosing and preventing over or underfeeding.Rate this question:
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- 40.
What chemical testing system would you use on a small, noncritical system?
- A.
Continuous.
- B.
Occasional.
- C.
Manual.
- D.
Spot.
Correct Answer
B. Occasional.Explanation
Occasional chemical testing would be suitable for a small, noncritical system because it does not require constant monitoring. Continuous testing would be unnecessary and potentially wasteful of resources, while manual testing would require regular human intervention. Spot testing, on the other hand, is typically used for specific, targeted analysis rather than general monitoring. Therefore, occasional testing strikes a balance between ensuring the system's chemical integrity without being overly burdensome.Rate this question:
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- 41.
When mixing chemicals in a mixing tank, you should not try to attain chemicalconcentrations greater than
- A.
3 percent
- B.
5 percent
- C.
7 percent
- D.
9 percent
Correct Answer
B. 5 percentExplanation
When mixing chemicals in a mixing tank, it is important not to try to attain chemical concentrations greater than 5 percent. This is because exceeding this concentration can lead to the chemicals becoming unstable or reactive, posing a safety risk. It is crucial to follow proper guidelines and protocols to ensure the safe handling and mixing of chemicals in order to prevent accidents or harmful reactions.Rate this question:
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- 42.
When you dilute any acid, you should always
- A.
Pour the acid into the water.
- B.
Pour the water into the acid.
- C.
Add the alkaline to the acid.
- D.
Add the acid to the alkaline.
Correct Answer
A. Pour the acid into the water.Explanation
When diluting any acid, it is important to pour the acid into the water rather than the other way around. This is because pouring water into acid can cause a violent reaction, leading to the acid splashing out of the container and potentially causing harm. On the other hand, pouring acid into water allows for better control of the reaction and minimizes the risk of splashing.Rate this question:
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- 43.
What reaction, if any, should you be aware of when mixing water and caustic soda?
- A.
None, if the mixture is accomplished quickly.
- B.
Enough heat generated to boil the mixture.
- C.
A mild reaction that could freeze the mixture.
- D.
A violent reaction that will solidify the mixture.
Correct Answer
B. Enough heat generated to boil the mixture.Explanation
When water and caustic soda are mixed, enough heat is generated to boil the mixture. This is because the reaction between water and caustic soda is exothermic, meaning it releases heat. The heat generated can be significant enough to cause the mixture to boil. It is important to be aware of this reaction and handle the mixture with caution to avoid any potential hazards.Rate this question:
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- 44.
In the event of any chemical contact with the skin, you should immediately
- A.
Rub the area vigorously with clean rags.
- B.
Cover the area and apply heat.
- C.
Flush the area with water.
- D.
Apply ice to the area.
Correct Answer
C. Flush the area with water.Explanation
When there is any chemical contact with the skin, it is important to flush the area with water immediately. This helps to remove the chemical from the skin and minimize its potential damage. Water can dilute and rinse away the chemical, preventing further absorption and reducing the risk of burns or other injuries. Rubbing the area vigorously with clean rags can actually worsen the situation by spreading the chemical or causing friction burns. Applying heat or ice may not be suitable as it can potentially worsen the chemical reaction or cause additional injuries.Rate this question:
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- 45.
What effect would dumping untreated water containing organic or nitrogen compoundshave on surface waters?
- A.
Increase the CO level in the water.
- B.
Decrease the CO level in the water.
- C.
Increase the O2 level in the water.
- D.
Decrease the O2 level in the water.
Correct Answer
D. Decrease the O2 level in the water.Explanation
Dumping untreated water containing organic or nitrogen compounds would lead to an increase in the level of nutrients in the water. These nutrients would promote the growth of algae and other aquatic plants, leading to an excessive growth known as algal bloom. As these plants die and decompose, the process consumes oxygen from the water, resulting in a decrease in the oxygen level. This can have detrimental effects on aquatic organisms, as they require oxygen to survive. Therefore, dumping untreated water with organic or nitrogen compounds would decrease the oxygen level in surface waters.Rate this question:
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- 46.
All corrosion occurs when electric current flows from the
- A.
Anode
- B.
Cathode
- C.
Electrolyte
- D.
Conductor
Correct Answer
A. AnodeExplanation
Corrosion occurs when electric current flows from the anode. The anode is the electrode where oxidation (loss of electrons) takes place during a chemical reaction. In the context of corrosion, the anode is the metal surface that undergoes oxidation, leading to the formation of metal ions and the breakdown of the material. The flow of electric current from the anode is responsible for the corrosion process, as it facilitates the transfer of electrons and the chemical reactions that cause the degradation of the metal.Rate this question:
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- 47.
Which type of corrosion can be described by saying that the anodic and cathodic areas canswitch back and forth?
- A.
Electrolytic
- B.
Galvanic
- C.
Uniform
- D.
Pitting
Correct Answer
C. UniformExplanation
Uniform corrosion occurs when the anodic and cathodic areas on a metal surface switch back and forth uniformly. This type of corrosion occurs evenly across the entire surface, resulting in a gradual loss of material. It is typically caused by exposure to a corrosive environment, such as moisture or chemicals, and can lead to the deterioration of the metal over time.Rate this question:
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- 48.
Which method of cathodic protection uses a rectifier?
- A.
Sacrificial anode system.
- B.
Sacrificial current system.
- C.
Impressed current system.
- D.
Impressed anode system.
Correct Answer
C. Impressed current system.Explanation
The method of cathodic protection that uses a rectifier is the impressed current system. This system involves the use of an external power source, typically a rectifier, to supply a controlled amount of direct current to the structure that needs protection. The rectifier converts alternating current to direct current and allows for the adjustment of the current output. This method is commonly used for larger structures or in situations where sacrificial anodes are not practical or effective.Rate this question:
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- 49.
What effect does too much bleedoff water have on cooling tower systems?
- A.
Higher water and utility expenses.
- B.
Reduction of system efficiency and utility expenses.
- C.
Lower water expenses and reduction of system efficiency.
- D.
Increase of system efficiency and higher water expenses.
Correct Answer
A. Higher water and utility expenses.Explanation
Too much bleedoff water in cooling tower systems leads to higher water and utility expenses. Bleedoff water refers to the water that is intentionally drained from the cooling tower to remove impurities and maintain water quality. If there is an excessive amount of bleedoff water, it means that more water is being wasted and discharged, resulting in higher water expenses. Additionally, the excessive bleedoff can also reduce the efficiency of the cooling tower system, leading to higher utility expenses.Rate this question:
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- 50.
What part of an HVAC/R system can be damaged by automotive types of antifreeze?
- A.
Pump seals
- B.
Mixing valves
- C.
Chilled water coil
- D.
Distribution piping
Correct Answer
A. Pump sealsExplanation
Automotive types of antifreeze can damage pump seals in an HVAC/R system. Pump seals are responsible for preventing leaks and maintaining the proper pressure within the system. Automotive antifreeze contains chemicals that can degrade the material of the pump seals over time, leading to leaks and reduced efficiency of the system. It is important to use the appropriate type of antifreeze specifically designed for HVAC/R systems to avoid damaging the pump seals and ensure the proper functioning of the system.Rate this question:
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Current Version
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Mar 20, 2023Quiz Edited by
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Jan 30, 2017Quiz Created by
Patricklittle101
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