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| The study of energy and its transformation. |
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| The relationship between chemical reactions and energy changes. |
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| The energy that an object possesses by virtue of its motion. |
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| The energy that an object possesses as a result of its composition or its position with respect to another object. |
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| The SI unit of energy, 1 kg-m2/s2. A related unit is the calorie: 4.184 J = 1 cal. |
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| A unit of energy, it is the amount of energy needed to raise the temperature of 1 g of water by 1°C, from 14.5°C to 15.5°C. A related unit is the joule: 1 cal = 4.184 J. |
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| In thermodynamics the portion of the universe that we single out for study. We must be careful to state exactly what the system contains and what transfers of energy it may have with its surroundings. |
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| In thermodynamics everything that lies outside the system that we study. |
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| The movement of an object against some force. |
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| The flow of energy from a body at higher temperature to one at a lower temperature when they are placed in thermal contact. |
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| The ability to do work or to transfer heat. |
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| first law of thermodynamics |
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Definition
A statement of our experience that energy is conserved in any process. We can express the law in many ways. One of the more useful expressions is that the change in internal energy, ΔE, of a system in any process is equal to the heat, q, added to they system, plus the work, w, done on the system by its surroundings: ΔE = q + w
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| The total energy possessed by a system. When a system undergoes a change, the change in internal energy, ΔE, is defined as the heat, q, added to they system, plus the work, w, done on they system by its surroundings: ΔE = q + w |
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| A process in which a system absorbs heat from its surroundings. |
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| A process in which a system releases heat to its surroundings. |
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| A property of a system that is determined by the state or condition of the system and not by how it got to that state; its value is fixed when temperature, pressure, composition, and physical form are specified; P, V, T, E, and H are state functions. |
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| A quantity defined by the relationship H = E + PV; the enthalpy change, ΔH, for a reaction that occurs at constant pressure is the heat evolved or absorbed in the reaction: ΔH = qP. |
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| The enthalpy change associated with a chemical reaction. |
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| The experimental measure of heat produced in chemical and physical processes. |
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| An apparatus that measures the evolution of heat. |
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| The quantity of heat required to raise the temperature of a sample of matter by 1°C (or 1 K). |
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| The heat required to raise the temperature of 1 mol of a substance by 1°C. |
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| specific heat (or specific heat capacity) |
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Definition
| The heat capacity of 1 g of a substance; the heat required to raise the temperature of 1 g of a substance by 1°C. |
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| A device for measuring the heat evolved in the combustion of a substance under constant-volume conditions. |
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| The heat evolved in a given process can be expressed as the sum of the heats of several processes that, when added, yield the process of interest. |
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| enthalpy (heat) of formation |
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Definition
| The enthalpy change that accompanies the formation of a substance from the most stable forms of its component elements. |
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| The enthalpy change when all reactants and products are at their standard states. |
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| standard enthalpy of formation (ΔH°f) |
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| The change in enthalpy that accompanies the formation of 1 mol of a substance from its elements, with all substance in their standard states. |
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| The energy released when 1 g of a substance is combusted. |
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| Coal, oil, and natural gas, which are presently our major sources of energy. |
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| A naturally occurring mixture of gaseous hydrocarbon compounds composed of hydrogen and carbon. |
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| A naturally occurring combustible liquid composed of hundreds of hydrocarbons and other organic compounds. |
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| A naturally occurring solid containing hydrocarbons of high molecular weight, as well as compounds containing sulfur, oxygen, and nitrogen. |
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| Energy such as solar energy, wind energy, and hydroelectric energy that is from essentially inexhaustible sources |
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