1.
Chemical reactions that absorb energy as they occur are called:
Correct Answer
B. Endothermic
Explanation
Endothermic reactions are chemical reactions that absorb energy from their surroundings as they occur. This means that the products of the reaction have more energy than the reactants, and the excess energy is usually absorbed as heat. This is in contrast to exothermic reactions, which release energy in the form of heat as they occur. Self-sustained is not a term used to describe a specific type of chemical reaction.
2.
Chemical reactions that give off energy as they occur are called:
Correct Answer
A. Exothermic
Explanation
Exothermic reactions release energy as they occur. This means that the products of the reaction have a lower energy level than the reactants, resulting in the release of heat or light. This energy release can be in the form of a flame, heat, or even an explosion. In contrast, endothermic reactions absorb energy from the surroundings, causing the products to have a higher energy level than the reactants. Self-sustained is not a term used to describe a type of chemical reaction.
3.
What is a chemical reaction that releases energy in the form of heat and light?
Correct Answer
A. Fire
Explanation
Fire is a chemical reaction that releases energy in the form of heat and light. When a combustible material combines with oxygen and is ignited, it undergoes a rapid oxidation process called combustion. This process releases energy in the form of heat and light, resulting in the phenomenon known as fire.
4.
What is the term used to define a chemical reaction involving the combination of oxygen with other materials?
Correct Answer
C. Oxidation
Explanation
Oxidation is the term used to define a chemical reaction involving the combination of oxygen with other materials. This process typically results in the loss of electrons by the oxidized substance and the gain of electrons by the oxygen. It is a common reaction that occurs in various natural and industrial processes, such as rusting of iron, burning of fuels, and metabolism in living organisms.
5.
In the flaming mode of combustion, what type of fuel is required?
Correct Answer
B. Gaseous
Explanation
In the flaming mode of combustion, gaseous fuel is required. This is because in flaming combustion, the fuel is vaporized and mixed with oxygen in the air to form a combustible mixture. The mixture then ignites and sustains a flame. Gaseous fuels, such as natural gas or propane, are already in a vaporized state and readily mix with oxygen, making them ideal for flaming combustion. Solid fuels would need to be converted into gaseous form before they can be used in flaming combustion. Atomized fuels, on the other hand, are in a fine spray form and are typically used in non-flaming combustion processes.
6.
What type of combustion is best described as solid fuel that is porous and charring on the surface?
Correct Answer
B. Smoldering
Explanation
Smoldering is the best description for solid fuel that is porous and charring on the surface. Smoldering combustion occurs when a material burns slowly with limited oxygen supply, resulting in the production of smoke and glowing embers. In this type of combustion, the fuel does not burn completely and instead chars on the surface, creating a smoldering and smoky fire. This is different from incipient combustion, which refers to the initial stage of a fire, and free burning combustion, which involves a rapid and complete burning of fuel.
7.
What are the components of the fire tetrahedron?
Correct Answer
C. Heat, fuel, oxygen, self-sustained chemical reaction
Explanation
The components of the fire tetrahedron are heat, fuel, oxygen, and self-sustained chemical reaction. These components are essential for a fire to occur and sustain itself. Heat provides the initial ignition source, fuel provides the material that can burn, oxygen supports the combustion process, and the self-sustained chemical reaction refers to the continuous release of energy through the combustion process. Without any of these components, a fire cannot start or continue to burn.
8.
Which two key factors influence the combustion process as it relates to fuel?
Correct Answer
C. pHysical state and distribution/orientation
Explanation
The combustion process is influenced by the physical state of the fuel, as different physical states (such as solid, liquid, or gas) have different combustion characteristics. The distribution/orientation of the fuel also plays a role, as the way the fuel is dispersed or arranged can affect the rate and efficiency of combustion.
9.
In which state must fuel be for flaming combustion to occur?
Correct Answer
B. Gaseous
Explanation
Flaming combustion occurs when a fuel is in a gaseous state. In this state, the fuel molecules are able to mix with oxygen in the air more easily, creating the necessary conditions for combustion to take place. When the fuel is heated, it can vaporize and become gaseous, allowing for flaming combustion to occur. Oxidized refers to a substance that has undergone a chemical reaction with oxygen, but it does not necessarily indicate the state of the fuel.
10.
The chemical decomposition of a substance through the action of heat is called:
Correct Answer
A. Pyrolysis
Explanation
Pyrolysis refers to the chemical decomposition of a substance caused by heat. This process involves the breaking down of complex molecules into simpler ones without the presence of oxygen. It is commonly used in various industries, such as the production of charcoal and the conversion of biomass into biofuels. Reduction and oxidation, on the other hand, involve the gain or loss of electrons and are not specifically related to the decomposition of substances through heat. Therefore, the correct answer for this question is pyrolysis.
11.
As the surface-to-mass ratio of a material increases, what affect does it have on ignition of that material?
Correct Answer
A. The fuel is more easily ignited.
Explanation
As the surface-to-mass ratio of a material increases, it means that the material has a larger surface area in proportion to its mass. This increased surface area allows for more contact with oxygen, which is necessary for combustion. Therefore, the fuel is more easily ignited because there is a greater opportunity for oxygen to react with the fuel molecules on the larger surface area.
12.
Which of the following would have the lowest surface-to-mass ratio?
Correct Answer
B. A log
Explanation
A log would have the lowest surface-to-mass ratio because it has a relatively large mass compared to its surface area. The surface-to-mass ratio is a measure of how much surface area an object has relative to its mass. Since a log is a solid and has a compact shape, it has a smaller surface area compared to its mass. On the other hand, a bucket of sawdust and a piece of lumber have more surface area relative to their mass due to their loose and elongated shapes.
13.
Which of the following liquids is heavier than water?
Correct Answer
C. Epichlorohydrin
Explanation
Epichlorohydrin is heavier than water because it has a higher density. Density is a measure of how much mass is packed into a given volume. If a liquid has a higher density than water, it means that a given volume of that liquid weighs more than the same volume of water. In this case, Epichlorohydrin has a higher density than water, making it heavier.
14.
What is flash point?
Correct Answer
B. The temperature at which a liquid releases sufficient vapors to ignite but not sustain combustion
Explanation
Flash point is the temperature at which a liquid releases enough vapors to ignite, meaning that it can catch fire when exposed to an ignition source. However, it does not sustain combustion, which means that the liquid will not continue to burn once the ignition source is removed.
15.
Which of the following describes a flammable liquid?
Correct Answer
B. A liquid with a flash point below 100*F (38*C)
Explanation
A flammable liquid is described as a liquid with a flash point below 100*F (38*C). The flash point is the lowest temperature at which the liquid can produce enough vapor to ignite when exposed to an open flame or spark. Therefore, a liquid with a flash point below 100*F (38*C) is more likely to catch fire or explode when in contact with a source of ignition.
16.
Which of the following describes a combustible liquid?
Correct Answer
A. A liquid with a flash point above 100*F (38*C)
Explanation
A combustible liquid is defined as a liquid with a flash point above 100*F (38*C). The flash point of a liquid is the lowest temperature at which it can vaporize to form an ignitable mixture in the air near its surface. Therefore, a liquid with a flash point above 100*F (38*C) is less likely to easily ignite compared to a liquid with a lower flash point.
17.
If a flammable liquid is spilled on the ground, which of the following explains the increased risks associated with fire?
Correct Answer
B. The surface area is increased and more vapors will be released.
Explanation
When a flammable liquid is spilled on the ground, the surface area is increased, which means that more of the liquid is exposed to the air. This increased surface area allows more vapors to be released into the surrounding environment. Since these vapors are flammable, the increased release of vapors increases the risk of fire.
18.
Which of the following best describes the results of using water-based foam designed for hydrocarbons on polar solvents?
Correct Answer
A. Polar solvents are soluble in water and the foam will mix with the solvent making the foam ineffective.
Explanation
The correct answer states that polar solvents are soluble in water and using water-based foam designed for hydrocarbons on polar solvents will cause the foam to mix with the solvent, rendering it ineffective. This is because the foam is not designed to handle polar solvents and cannot effectively control the fire in this situation.
19.
What will happen to a vapor given off by a flammable liquid with a vapor density of 2.3?
Correct Answer
C. The vapor will sink.
Explanation
Given that the vapor density of the flammable liquid is 2.3, which is greater than the density of air (approximately 1), it indicates that the vapor is heavier than air. Therefore, the vapor will have a tendency to sink rather than rise or hover.
20.
How does oxygen contribute to the burning process?
Correct Answer
C. Oxygen is the primary oxidizing agent in most fires.
Explanation
Oxygen is the primary oxidizing agent in most fires because it supports the combustion process by reacting with the fuel. When a fire occurs, oxygen molecules combine with the fuel molecules, releasing energy in the form of heat and light. This process, known as oxidation, sustains the burning process and allows the fire to continue. Without oxygen, fires cannot burn or sustain themselves. Therefore, oxygen's role as the primary oxidizing agent is crucial in the burning process.
21.
Which of the following statements about oxygen concentrations and combustion is MOST accurate?
Correct Answer
A. Combustion may occur at oxygen concentrations as low as 14% or lower given the right circumstances.
Explanation
Combustion may occur at oxygen concentrations as low as 14% or lower given the right circumstances. This means that under certain conditions, such as the presence of a flammable substance or high temperatures, combustion can still happen even with a relatively low oxygen concentration.
22.
Which of the following best describes how higher concentrations of oxygen affect materials in fire conditions?
Correct Answer
C. Materials that burn at normal oxygen levels will burn more intensely.
Explanation
Higher concentrations of oxygen in fire conditions can lead to a more intense burning of materials that already burn in normal oxygen levels. This is because oxygen supports the combustion process by providing the necessary fuel for the fire. When there is an increased supply of oxygen, the fire can burn more vigorously and release more heat and energy. Therefore, materials that burn at normal oxygen levels will burn more intensely in the presence of higher oxygen concentrations.
23.
Which of the following is defined as the range of vapor concentration that will support combustion?
Correct Answer
C. Flammable range
Explanation
The flammable range is defined as the range of vapor concentration that will support combustion. It represents the lower and upper limits of concentration within which a flammable substance can ignite and sustain a fire or explosion. Concentrations below the lower limit are too lean to ignite, while concentrations above the upper limit are too rich to ignite. Understanding the flammable range is crucial for assessing the potential fire or explosion hazards of a substance in different environments.
24.
What form of energy is defined as energy associated with the movement of the atoms and molecules that comprise matter?
Correct Answer
B. Kinetic
Explanation
Kinetic energy is defined as the energy associated with the movement of atoms and molecules that make up matter. It is the energy that an object possesses due to its motion. When atoms and molecules move, they have kinetic energy. Therefore, the correct answer is kinetic.
25.
What term is defined as the capacity to perform work, and occurs when a force is applied to an object over a distance or when a chemical, biological, or physical transformation is made in a substance?
Correct Answer
B. Energy
Explanation
Energy is the correct answer because it is defined as the capacity to perform work. It is the ability to cause change or do work, and it can manifest in various forms such as mechanical, chemical, thermal, or electrical energy. When a force is applied to an object over a distance or when a transformation occurs in a substance, energy is involved in the process.
26.
The measure of a material's ability to transfer heat energy to other objects is known as:
Correct Answer
C. Temperature
Explanation
Temperature is the measure of the average kinetic energy of the particles in a substance. It determines the direction of heat transfer, with heat flowing from objects at higher temperatures to objects at lower temperatures. Therefore, temperature is a measure of a material's ability to transfer heat energy to other objects. Force and energy are not directly related to the transfer of heat energy.
27.
What type of ignition occurs when a mixture of fuel and oxygen encounters an external heat source with sufficient heat energy to start the combustion reaction?
Correct Answer
B. Piloted ignition
Explanation
Piloted ignition occurs when a mixture of fuel and oxygen encounters an external heat source with sufficient heat energy to start the combustion reaction. In this type of ignition, the external heat source acts as a pilot flame that ignites the fuel and oxygen mixture, initiating the combustion process. This differs from autoignition, where the fuel and oxygen mixture spontaneously ignites without the need for an external heat source, and exothermic ignition, which refers to the release of heat energy during the combustion process.
28.
What type of ignition occurs without an external flame or spark to ignite the fuel gases as vapors?
Correct Answer
A. Autoignition
Explanation
Autoignition refers to the process in which a fuel-air mixture ignites spontaneously without the need for an external flame or spark. This occurs when the temperature of the mixture reaches a certain threshold, known as the autoignition temperature. At this temperature, the fuel gases as vapors undergo a self-sustaining combustion reaction, leading to ignition. Autoignition is commonly observed in engines, where the compression of the fuel-air mixture raises its temperature to the autoignition temperature, causing ignition without the need for an external ignition source.
29.
Chemical heat energy is created under which of the following conditions?
Correct Answer
B. When two or more chemicals combine and react with one another
Explanation
Chemical heat energy is created when two or more chemicals combine and react with one another. This is because chemical reactions involve the breaking and forming of chemical bonds, which releases or absorbs energy. When two or more chemicals react, the bonds in the reactants are broken, and new bonds are formed in the products. This bond formation releases energy in the form of heat, resulting in an increase in temperature. Therefore, the correct answer is when two or more chemicals combine and react with one another.
30.
Which of the following best defines self-heating (spontaneous heating)?
Correct Answer
B. Heating that occurs when a material increases in temperature without the addition of external heat
Explanation
Self-heating, also known as spontaneous heating, refers to the phenomenon where a material increases in temperature without the addition of external heat. This can occur due to exothermic chemical reactions, such as oxidation or decomposition, happening within the material itself. The internal heat generated by these reactions causes the temperature of the material to rise. It is important to note that self-heating can be dangerous as it may lead to fires or explosions if not properly managed.
31.
What is the primary hazard created by electrical overcurrent or overload?
Correct Answer
A. A conductor may overheat and present an ignition hazard
Explanation
When there is an electrical overcurrent or overload, it means that the current flowing through a conductor exceeds its rated capacity. This can cause the conductor to overheat, which in turn can lead to ignition of nearby combustible materials. Therefore, the primary hazard created by electrical overcurrent or overload is that a conductor may overheat and present an ignition hazard.
32.
What is a form of heat energy generated by friction or compression?
Correct Answer
A. Mechanical heat energy
Explanation
Mechanical heat energy is a form of heat energy that is generated by friction or compression. When two objects rub against each other or when pressure is applied to an object, the mechanical energy is converted into heat energy. This transfer of energy occurs due to the movement and interaction of the particles within the objects. Therefore, mechanical heat energy is a result of the conversion of mechanical energy into heat energy through friction or compression.
33.
What type of mechanism transfers heat from one object to another by direct contact?
Correct Answer
C. Conduction
Explanation
Conduction is the process by which heat is transferred from one object to another through direct contact. In this mechanism, heat energy is passed from molecule to molecule within a substance or between different substances that are in direct contact. It occurs when there is a difference in temperature between the objects, causing the molecules with higher energy to transfer heat to the molecules with lower energy. Unlike radiation and convection, conduction does not involve the movement of particles or electromagnetic waves.
34.
What type of mechanism transfers heat from a liquid or gas to a solid surface?
Correct Answer
B. Convection
Explanation
Convection is the type of mechanism that transfers heat from a liquid or gas to a solid surface. This process involves the movement of the heated particles in the liquid or gas, which then come into contact with the solid surface and transfer their heat energy. Convection is commonly observed in everyday life, such as when hot air rises and transfers heat to a cooler surface.
35.
What type of mechanism transfers heat as an electromagnetic wave without an intervening medium?
Correct Answer
A. Radiation
Explanation
Radiation is the correct answer because it is the type of mechanism that transfers heat as an electromagnetic wave without the need for a medium. Unlike convection, which requires the movement of particles in a fluid, and direct flame contact, which requires physical contact between objects, radiation can occur through empty space. This is because electromagnetic waves, such as infrared radiation, can travel through a vacuum and transfer heat energy from a source to a receiver without the need for any intervening medium.
36.
Although fuel moisture would be considered a passive agent in the combustion process, how would fuel moisture have a significant effect on ignition and fire development?
Correct Answer
C. The moisture slows absorption of heat energy and the ignition and combustion process.
Explanation
Fuel moisture slows down the absorption of heat energy and the ignition and combustion process. When fuel has a higher moisture content, it takes longer for the heat to be absorbed by the fuel. This delay in heat absorption can prevent the fuel from reaching its ignition temperature quickly, thus slowing down the ignition process. Additionally, the presence of moisture can also hinder the combustion process by reducing the availability of combustible material and making it more difficult for the fire to spread.
37.
Which of the following best describes the self-sustained chemical reaction in the flaming combustion process?
Correct Answer
B. Fuel molecules and oxygen break apart to form free radicals,, then combine with available fuel and oxygen to form intermediate combustion products.
Explanation
In the self-sustained chemical reaction in the flaming combustion process, fuel molecules and oxygen break apart to form free radicals. These free radicals then combine with available fuel and oxygen to form intermediate combustion products. This process allows for a continuous chain reaction, where the free radicals generated from the initial breakdown of fuel molecules and oxygen continue to react with more fuel, creating a sustained combustion process.
38.
Why are products of uncontrolled combustion a concern to fire service personnel?
Correct Answer
C. Combustion produces a wide range of products including toxic and flammable gases, vapors, and particulates.
Explanation
The products of uncontrolled combustion are a concern to fire service personnel because they can be toxic and flammable. These products include gases, vapors, and particulates that can be harmful to both the environment and human health. In addition, the release of these combustion by-products contributes to air pollution and can worsen global warming. Therefore, fire service personnel need to be cautious and take appropriate measures to minimize the impact of these products during firefighting operations.
39.
A fire involving ordinary, solid, combustible materials such as wood, cloth, paper, rubber, and many plastics is a _______ fire.
Correct Answer
A. Class A
Explanation
A fire involving ordinary, solid, combustible materials such as wood, cloth, paper, rubber, and many plastics is classified as a Class A fire. This classification is used to categorize fires based on the type of fuel involved. Class A fires are commonly found in homes and offices and can be extinguished using water or other common firefighting agents.
40.
A fire involving energized electrical equipment is a ______ fire.
Correct Answer
C. Class C
Explanation
A fire involving energized electrical equipment is classified as a Class C fire. This type of fire is specifically caused by electrical faults or malfunctions in electrical devices, wiring, or circuits. Class C fires are unique because they involve the presence of electricity, which poses an additional risk to firefighters and individuals attempting to extinguish the fire. The use of water-based extinguishing agents is not recommended for Class C fires, as it can conduct electricity and potentially lead to electric shock. Instead, carbon dioxide or dry chemical extinguishers are typically used to suppress the fire and eliminate the electrical source.
41.
A fire involving oils and greases normally found in commercial kitchens and food preparation facilities using deep fryers is a ______ fire.
Correct Answer
C. Class K
Explanation
A fire involving oils and greases normally found in commercial kitchens and food preparation facilities using deep fryers is classified as a Class K fire. Class K fires are specifically designated for fires involving cooking oils and fats, such as vegetable oil, animal fat, and grease. These fires require specialized suppression systems and extinguishing agents designed to effectively combat the high temperatures and re-ignition potential of these substances.
42.
A fire involving flammable and combustible liquids and gases such as gasoline, oil, lacquer, paint, mineral spirits, and alcohol is a ______ fire.
Correct Answer
B. Class B
Explanation
A fire involving flammable and combustible liquids and gases such as gasoline, oil, lacquer, paint, mineral spirits, and alcohol is classified as a Class B fire. Class B fires involve flammable liquids and gases, and are typically extinguished using foam, dry chemical, or carbon dioxide extinguishers. Class A fires, on the other hand, involve ordinary combustible materials like wood, paper, and fabric, while Class C fires involve energized electrical equipment.
43.
A fire involving combustible metals such as aluminum, magnesium, potassium, sodium, titanium, and zirconium is a ______ fire.
Correct Answer
C. Class D
Explanation
A fire involving combustible metals such as aluminum, magnesium, potassium, sodium, titanium, and zirconium is classified as a Class D fire. This classification is used to identify fires caused by combustible metals, which require specific extinguishing agents and techniques to effectively control and extinguish the fire. Class D fires can be highly dangerous and require specialized training and equipment to handle safely.