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40 Cards in this Set
- Front
- Back
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What is matter?
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Matter is anything that occupies space and has mass.
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What is a physical change?
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A physical change occurs when a substance remains chemically unchanged but changes in size, shape, or appearance.
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What is a chemical change?
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A chemical change occurs when a substance changes from one type of matter into another, such as two or more substances combining to form compounds.
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What is energy?
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Energy is the capacity to perform work.
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What is potential energy? |
Potential energy represents the amout of kinetic energy that an object can release at some point in the future (ex. Fuels before they burn) |
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What is kinetic energy?
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Kinetic energy is the energy possessed by a moving object. (ex. Fuel while burning - since the molecules are vibrating more and more rapidly)
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What are exothermic reactions?
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Chemical reactions that release thermal energy or heat
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What are endothermic reactions?
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Chemical reactions that absorb thermal energy or heat
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What is vaporization?
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Vaporization defined is a physical process that changes a liquid into a gaseous state.
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What are the two forms of ignition?
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Piloted
Non-Piloted (Auto Ignition) |
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What is Auto Ignition Temperature?
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the lowest temperature at which a combustible material will ignite without an external source of ignition
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What are the two modes of combustion?
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Flaming (occurs when a gaseous fuel mixes with oxygen in the correct ratio and is heated to ignition temperature).
Non-flaming (occurs more slowly at lower temperature producing a smoldering glow in the material’s surface). |
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What is the definition of Fire?
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Fire defined is a rapid oxidation process, which is a chemical reaction resulting in the evolution of light and heat in varying intensities.
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What is the definition of Combustion?
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Combustion defined is a chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light in the form of either a glow or a flame.
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What is smoke?
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The product of incomplete combustion
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What are some common products of combustion?
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What are 3 common sources of thermal energy? |
(Light, Nuclear, and Sound are less common sources of thermal energy) |
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Name 4 of the ways electrical heating can occur.
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Resistance heating
Overcurrent/Overload Arcing (through a gap) Sparking (spatters) |
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Name 3 of the ways mechanical energy/heat is created.
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Adiabatic Compression (compressing gas)
Friction (surfaces rubbing) Friction Sparks (two hard surfaces) |
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What is conduction?
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Is the transfer of heat through or between solids that are in direct contact.
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What is convection?
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Is the transfer of thermal energy by the circulation or movement of a fluid (liquid or gas)
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What is radiation?
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Is the transmission of energy as an electromagnetic wave, such as light waves, radio waves, or X-rays, without an intervening medium.
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What is heat of combustion?
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the total amount of thermal energy (heat) that could be generated by the combustion (oxidation) reaction if a fuel were completely burned.
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What is Heat Release Rate (HRR)?
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total amount of heat released per unit time and is measured in kilowatts (kW).
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What is pyrolysis?
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the chemical decomposition of a solid material by heating
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What is specific gravity?
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the ratio of the mass of a given volume of a liquid compared with the mass of an equal volume of water at the same temperature.
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Describe vapor pressure.
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In order for vaporization to occur, the escaping vapors must be at a higher pressure than atmospheric pressure. The pressure that vapors escaping from a liquid exert is known as vapor pressure.
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What is flashpoint?
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the minimum temperature at which a liquid gives off sufficient vapors to form an ignitable mixture with air near the liquid’s surface.
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What is fire point?
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the temperature at which sufficient vapors are being generated to sustain the combustion reaction.
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Define LEL.
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the lowest concentration of a combustible or flammable gas in air that will support combustion.
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Define UEL.
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highest concentration of a combustible or flammable gas in air that will support combustion.
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What is vapor density?
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Vapor density describes the density of gases in relation to air. Air has been assigned a vapour density of 1.
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What is an oxidizing agent?
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An oxidizing agent is any substance that yields oxygen during a chemical reaction. An oxidizer is not combustible but it will support combustion.
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What is a compartment fire called when fuel is limited?
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Fuel Controlled
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What is a compartment fire called when oxygen is limited?
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Ventilation Controlled
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What are the 4 stages of fire Development?
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Incipient
Growth Fully Developed Decay |
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What is the escape time from a room involved in a flashover?
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0.5 - 2 seconds (about 5 feet from the door)
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What are some of the precursors for a flashover? (4) |
Free burning
High Temperatures
Heavy dark smoke
Rollover |
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What is a smoke explosion?
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It is the ignition of a premixed pocket of fire gases and oxygen that may occur when an ignition source is introduced. This could be the smoke finding an ignition source elsewhere or an ignition source being brought to the smoke.
Conditions for smoke explosion requires fuel/air mixture to be less than 600 C (otherwise it would have auto-ignited) |
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As a "very combustible fuel", what is the flammable range of carbon monoxide? |
12.5% - 74%
Ignites at 610 degrees C |
