Chapter Test 4 (IFSTA 7th Edition) SOLUTION 2023//2024

Chapter Test 4 (IFSTA 7th Edition) SOLUTION 2023//2024 Fires involve a heat-producing chemical reaction between fuel and: (117) [4.3.11] A. a catalyst. B. an oxidizer. C. free radicals. D. a reducing agent. - ANSWER B. an oxidizer When a substance changes from one type of matter into another, such as two or more substances combining to form compounds, the substance undergoes a: (118) [4.3.11] A. dissolution. B. metamorphosis. C. chemical reaction. D. physiological change. - ANSWER C. chemical reaction Which statement about energy and combustion is accurate? (120) [4.3.11] A. A fuel's chemical energy is the result of rapid vibrations in the molecules. B. Chemical and physical changes almost never involve an exchange of energy. C. A fuel's potential energy releases during combustion and converts to kinetic energy. D. Chemical changes involve an exchange of energy; physical changes involve no energy exchange. - ANSWER C. A fuel's potential energy releases during combustion and converts to kinetic energy. Which element of the fire tetrahedron is included to explain flaming (gas-phase) combustion? (120) [4.3.11] A. Fuel B. Heat C. Oxygen D. Chemical chain reaction - ANSWER D. Chemical chain reaction What occurs when a mixture of fuel and oxygen encounter an external heat source with sufficient heat or thermal energy to start the combustion reaction? (120) [4.3.11] A. Autoignition B. Piloted ignition C. Kinetic ignition D. Sustained ignition - ANSWER B. Piloted ignition The minimum temperature at which a fuel in the air must be heated in order to start selfsustained combustion is known as the: (122) [4.3.11] A. autoignition temperature (AIT). B. piloted ignition temperature (PIT). C. lower explosive (flammable) limit (LEL). D. upper explosive (flammable) limit (UEL). - ANSWER A. autoignition temperature (AIT). What causes flaming combustion to occur? (123) [4.3.11] A. A solid fuel encounters an open flame and entrain enough air to ignite. B. A gaseous fuel encounters an external heat source and experience piloted ignition. C. A gaseous fuel mixes with an adequate amount of oxygen and heats to ignition temperature. D. A solid fuel mixes with an adequate amount of liquid fuel to be able to sustain an open burning flame. - ANSWER C. A gaseous fuel mixes with an adequate amount of oxygen and heats to ignition temperature.