1.
Which factor complicates the use of a combustible gas indicator?
Correct Answer
C. The instrument is calibrated for only one specific gas.
Explanation
The use of a combustible gas indicator is complicated by the fact that the instrument is calibrated for only one specific gas. This means that it may not accurately detect or measure other gases, leading to potential safety risks if different gases are present. It is important to use the correct instrument calibrated for the specific gas being measured to ensure accurate readings and proper safety precautions.
2.
Situational awareness begins with:
Correct Answer
D. Obtaining information about the situation.
Explanation
Situational awareness refers to the ability to perceive and understand the current situation. In order to have situational awareness, it is important to gather information about the situation. This involves obtaining relevant data, facts, and details about the environment, events, and potential threats or risks. By obtaining information about the situation, individuals can make informed decisions, assess risks, and effectively respond to the circumstances at hand.
3.
What is the most commonly encountered source of carbon monoxide?
Correct Answer
B. Combustion
Explanation
Combustion is the most commonly encountered source of carbon monoxide. Combustion is the process of burning, which occurs when a substance reacts with oxygen to produce heat and light. Carbon monoxide is a byproduct of incomplete combustion, where there is insufficient oxygen available for the fuel to completely burn. This can happen in various situations, such as when using fuel-burning appliances like stoves, furnaces, or generators, or when burning wood or charcoal. Carbon monoxide is a dangerous gas that is odorless and colorless, and can be fatal if inhaled in high concentrations.
4.
Ambient air at sea level contains _____% oxygen.
Correct Answer
A. 20.9
Explanation
The correct answer is 20.9. Ambient air at sea level contains approximately 20.9% oxygen. This is the average concentration of oxygen in the Earth's atmosphere and is necessary for the survival of most living organisms.
5.
Which of the following pH levels is acidic?
Correct Answer
B. 2
Explanation
A pH level of 2 is considered acidic because it falls below the neutral pH level of 7. The pH scale ranges from 0 to 14, with values below 7 indicating acidity. A pH level of 2 suggests a high concentration of hydrogen ions, which is characteristic of acidic substances.
6.
What does pH measure?
Correct Answer
D. The concentration of hydrogen ions
Explanation
pH measures the concentration of hydrogen ions in a solution. It is a measure of the acidity or alkalinity of a substance. The pH scale ranges from 0 to 14, with 7 being neutral, values below 7 indicating acidity, and values above 7 indicating alkalinity. The concentration of hydrogen ions determines the pH value, with higher concentrations of hydrogen ions resulting in lower pH values, indicating greater acidity. pH is an important parameter in various fields, including chemistry, biology, and environmental science, as it affects chemical reactions, enzyme activity, and the behavior of substances in solution.
7.
What is a neutral pH?
Correct Answer
B. 7
Explanation
A neutral pH refers to a substance or solution that is neither acidic nor basic. It is considered neutral when it has a pH value of 7. At this pH level, the concentration of hydrogen ions (H+) is equal to the concentration of hydroxide ions (OH-), resulting in a balanced solution. This means that a neutral pH is neither acidic (pH below 7) nor basic (pH above 7).
8.
An oxygen-deficient atmosphere is defined as an oxygen concentration below _____%.
Correct Answer
C. 19.5
Explanation
An oxygen-deficient atmosphere is defined as an oxygen concentration below 19.5%. This means that if the oxygen concentration in the atmosphere falls below this threshold, it can be considered oxygen-deficient. This is important because a lack of oxygen can be dangerous and potentially life-threatening, as it can lead to difficulty breathing, dizziness, and even loss of consciousness. Therefore, it is crucial to ensure that the oxygen concentration in the atmosphere remains above 19.5% to maintain a safe environment.
9.
What is used to measure the pH of corrosive liquids and gases?
Correct Answer
B. Litmus paper
Explanation
Litmus paper is used to measure the pH of corrosive liquids and gases. It is a simple and inexpensive method to determine the acidity or alkalinity of a substance. Litmus paper contains a mixture of dyes that change color depending on the pH of the solution. When dipped into a sample, the litmus paper will turn red if the solution is acidic, blue if it is alkaline, or remain unchanged if it is neutral. This allows for a quick and easy assessment of the pH level, making it a suitable tool for measuring the pH of corrosive substances.
10.
When performing atmospheric monitoring of a building, where should you start?
Correct Answer
C. Around the outside of the building
Explanation
When performing atmospheric monitoring of a building, it is best to start around the outside of the building. This is because starting from the outside allows for a comprehensive assessment of the surrounding environment and potential sources of pollutants or hazardous substances. By starting at the perimeter, one can identify any potential risks or sources of contamination before entering the building, ensuring a safer monitoring process.
11.
What is the primary toxic effect of carbon monoxide?
Correct Answer
A. Interferes with the blood's ability to carry oxygen
Explanation
Carbon monoxide is a toxic gas that binds to hemoglobin in the blood, forming carboxyhemoglobin. This reduces the blood's ability to carry oxygen to the body's tissues, leading to oxygen deprivation. This can result in symptoms such as headache, dizziness, confusion, and eventually, if not treated, can be fatal. Therefore, the primary toxic effect of carbon monoxide is that it interferes with the blood's ability to carry oxygen.
12.
What is the term for a quick field test to ensure that a gas detector will detect the gases it is intended to?
Correct Answer
C. Bump test
Explanation
A bump test is a quick field test conducted to ensure that a gas detector can detect the gases it is designed to detect. This test involves exposing the gas detector to a known concentration of gas and checking if it triggers an alarm. The purpose of the bump test is to verify that the sensor and alarm functions are working properly. It is a simple and efficient way to ensure the reliability and accuracy of gas detectors before they are used in potentially hazardous environments.
13.
Which of the following pH levels is the most corrosive?
Correct Answer
C. 12
Explanation
A pH level of 12 is the most corrosive because it is highly alkaline. Alkaline substances have a high concentration of hydroxide ions, which can react with metals and other materials, causing corrosion. Lower pH levels indicate acidity, which can also be corrosive, but a pH level of 12 is significantly more alkaline and therefore more corrosive than the other options given.
14.
A __________ is clipped to a front shirt pocket and measures exposure to a specific contaminant.
Correct Answer
D. Personal dosimeter
Explanation
A personal dosimeter is a device that is clipped to a front shirt pocket and is used to measure exposure to a specific contaminant. It is designed to monitor and track the amount of exposure an individual receives to a particular substance, such as radiation or chemicals. This device is commonly used in industries where workers may be exposed to hazardous materials, allowing them to monitor their exposure levels and take necessary precautions to protect their health and safety.
15.
Which of the following detection devices is dipped into an unknown liquid, allowing the chemical to come into contact with several small “windows,” each with specific reagents designed to identify the presence of different chemical classifications?
Correct Answer
D. Chemical test strip
Explanation
A chemical test strip is a detection device that is dipped into an unknown liquid to identify the presence of different chemical classifications. It contains several small "windows" with specific reagents designed to react with different types of chemicals. By observing the color changes or other reactions in the windows, one can determine the presence or absence of certain chemicals in the liquid. This makes chemical test strips a convenient and efficient tool for quickly identifying the composition of a substance.
16.
Most combustible-gas indicators begin to alarm when the concentration of combustible gas reaches what level?
Correct Answer
C. 10% of the LEL/LFL
Explanation
Most combustible-gas indicators begin to alarm when the concentration of combustible gas reaches 10% of the lower explosive limit (LEL)/lower flammable limit (LFL). This means that the alarm will sound when the gas concentration is at a level that is 10% of the minimum concentration required for an explosion or fire to occur. This is a safety precaution to alert individuals to the presence of potentially dangerous levels of combustible gas before it reaches a critical point.
17.
Which item is required to zero a gas detector?
Correct Answer
B. Clean atmospHere
Explanation
A clean atmosphere is required to zero a gas detector because zeroing a gas detector means setting it to a baseline reading of zero in the absence of any gas. This is done by exposing the detector to a clean atmosphere, free from any gas or contaminants, so that it can accurately measure and display zero levels. Calibration gas is used to calibrate the detector for specific gases, but it is not required for zeroing. Bump gas is used to quickly check the functionality of the detector, but it is also not necessary for zeroing.
18.
The reagent in __________ will undergo a particular color change when exposed to the contaminant it is designed to detect.
Correct Answer
D. A colorimetric tube
Explanation
A colorimetric tube is designed to detect contaminants by undergoing a particular color change when exposed to the contaminant. This means that when the reagent in the colorimetric tube comes into contact with the contaminant, it will react chemically and produce a visible color change. This color change can then be used to identify the presence of the contaminant.
19.
Which procedure ensures that a particular instrument will detect the gas or vapor it is intended to detect at a certain level?
Correct Answer
C. Calibration
Explanation
Calibration is the process that ensures a specific instrument can accurately detect a particular gas or vapor at a certain level. During calibration, the instrument is adjusted and tested against known reference standards to ensure its readings are accurate and reliable. This process helps to maintain the instrument's performance and reliability, ensuring it can effectively detect the intended gas or vapor at the desired level.
20.
Which type of gas detector uses a hand-powered bellows pump to draw a sample?
Correct Answer
B. Colorimetric tube
Explanation
A colorimetric tube is a type of gas detector that uses a hand-powered bellows pump to draw a sample. These tubes contain a chemical reagent that changes color when it comes into contact with a specific gas. By pumping the bellows, a sample of air is drawn through the tube, and if the target gas is present, the reagent will change color, indicating its presence. This type of gas detector is commonly used for spot testing in various industries to quickly identify the presence of specific gases.
21.
What is the minimum concentration of atmospheric oxygen necessary for a combustible gas indicator to function properly?
Correct Answer
B. 10%
Explanation
A combustible gas indicator is a device used to detect the presence of flammable gases in the air. In order for it to function properly, there needs to be a minimum concentration of atmospheric oxygen. The correct answer is 10%, which means that at least 10% of the air needs to be oxygen for the combustible gas indicator to work effectively. This is because oxygen is necessary for combustion to occur, and without a sufficient amount of oxygen, the indicator may not be able to accurately detect the presence of flammable gases.
22.
A __________ is a versatile detection device typically equipped with a combination of toxic gas sensors and the ability to detect flammable gases and vapors.
Correct Answer
B. Multi-gas meter
Explanation
A multi-gas meter is a versatile detection device that is equipped with a combination of toxic gas sensors and the ability to detect flammable gases and vapors. This device is capable of detecting a wide range of gases and is therefore considered versatile. It is commonly used in various industries and applications where the detection of multiple types of gases is required for safety purposes.
23.
What is the minimum concentration of carbon monoxide at which all emergency personnel should wear self-contained breathing apparatus?
Correct Answer
A. 35 parts per million (ppm)
Explanation
The minimum concentration of carbon monoxide at which all emergency personnel should wear self-contained breathing apparatus is 35 parts per million (ppm). This indicates that even at this relatively low concentration, carbon monoxide can pose a significant risk to the health and safety of emergency personnel. Wearing self-contained breathing apparatus is necessary to prevent inhalation of carbon monoxide and potential poisoning. Higher concentrations, such as 475 ppm, 2000 ppm, or 1000 ppm, would likely require even more stringent safety measures and precautions.
24.
The time it takes for a gas detector to draw in an air sample, process the sample, and give a reading is the __________ time.
Correct Answer
A. Reaction
Explanation
The time it takes for a gas detector to draw in an air sample, process the sample, and give a reading is referred to as the reaction time. This term encompasses the entire process of detecting and analyzing the gas sample, including any necessary chemical reactions or physical transformations that occur within the detector.
25.
Which instrument uses a tiny hydrogen flame to break down a sample gas into electrically charged particles to determine the concentration of each component of the gaseous mixture?
Correct Answer
A. Flame ionization detector
Explanation
The flame ionization detector uses a tiny hydrogen flame to break down a sample gas into electrically charged particles. This process allows the detector to determine the concentration of each component of the gaseous mixture. Gas chromatography, Raman spectroscopy, and Transform infrared spectroscopy are not specifically designed to perform this function, making them incorrect answers.