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Definition
| The study of energy changes that occur during chemical reactions and changes in states. |
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| Chemical Potential Energy |
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Definition
| Engergy strored in chemical bonds |
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Definition
| (represented by q) is energy transfers from one object to another because of a temperature differance between them. |
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| (represented by q) is energy transfers from one object to another because of a temperature differance between them. *Key Concept: heat always flows from a warmer object to a cooler object* |
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Definition
| The part of the universe on which you focus your attention. |
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Definition
| Everything else in the universe not including the system. (The immediate vicinity of the systems surroundings in terms of thermochemistry) |
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| Law of Conservation of Energy |
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Definition
| In any chemical or physical change, energy is neither created nor destroyed. If the energy of a system decreases, then the energy of the surroundings increases so the total energy remains the same. |
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Definition
| Absorbs heat from the surroundings *Key Concept: In an endothermic reaction, the surrounding cools down (measured temerature)* |
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Definition
| One that releases heat to its surroundings. *Key Concept: the system looses heat, so the surroundings (measured temperature) heats up* |
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Definition
| the quantity of heat needed to raise the temperature of pur water 1*C. One dietary Calorie equals 1000 calories, or one kilocalorie |
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Term
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Definition
| the SI unit of energy. One joule raises the temperature of one gram of pure water .2390*C |
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Definition
| The amount of heat needed to increase the temprature of an object exactly one degree celcius. *Key Concept: the heat capacity of an object depends on the mass and chemical composition* |
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Definition
| the amount of heat it takes to raise thte temperature of 1 gram of a substance 1*C. See table 17.1 on page 508. |
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| Calculation for specific heat of a substance |
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Definition
| specific heat (C)= heat (q) in joules / mass (m) in grams * change in temperature (degrees Celcius) |
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Term
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Definition
| the precise measurement of the heat flow into or out of a system. *Key Concept: In calorimetry, the heat released from a system is equal to the heat absorbed by the surroundings. Conversely, the heat absorbed by a system is equal to the heat released by the surroundings.* |
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Definition
| the insulated device used to measure the absorption or release of heat in a chemical or physical process. |
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Definition
The heat content of the system at constant pressure.
q=change in H |
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| A chemical equation including enthalpy of change. *Key Concept: In a chemical equation, the enthalpy of change for the reaction can be written as either a reactant of a product.* |
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Term
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Definition
| the enthalpy change of a reaction exactly as it is written. |
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Definition
| The heat of reaction for the complete burning of one mole of a substance. |
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Definition
| The amount of energy as heat absorbed by one mole of a solid substance as it melts to a liquid at constant temperature. *Key Concept: The quantity of heat as energy absorbed by a melting solid is exactly the same as the quantity of heat released when the liquid solidifies.* |
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| Molar Heat of Solidification |
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Definition
| The amount of energy as heat lost when one mole of a liquid solidifies at constant temperature. *Key Concept: The quantity of heat as energy absorbed by a melting solid is exactly the same as the quantity of heat released when the liquid solidifies.* |
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| Molar Heat of Vaporization |
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Definition
| The amount of energy as heat needed to vaporize one mole of a given liquid. (See Table 17.3)*Key Concept: The quantity of heat absorbed by a vaporizing liquid is exactly the same as the quantity of the energy as heat released when it condenses.* |
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| Molar Heat of Condensation |
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Definition
| The amount of energy as heat released when one mole of a gas condenses at its normal boiling point. *Key Concept: The quantity of heat absorbed by a vaporizing liquid is exactly the same as the quantity of the energy as heat released when it condenses.* |
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Definition
| The enthalpy change caused by thedissolution of one mole of a substance. *Key Concept: During the formaton of a solution, heat is either released or absorbed.* |
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| Hess's Law of Heat Summation |
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Definition
| If you can add together two or more thermochemical equation to give a final equation, then you can also add the energy as heat of the reactions to come up with the heat of the final reaction. *Key Concept: Hess's Law allows you to determine the heat of a reaction indirectly.* |
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| Standard Heat of Formation |
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Definition
| The change in enthalpy that accompanies the formation of one mole of a compound from its elements in their standard states at 25*C and 101.3 kPa *Key Concept: For a reaction that occurs at standard conditions, you can calculate the heat of reaction by using standard heat of formation ((Delta)Standard heat of reaction= (delta)standard heat of formation products-(delta)standard heat of formation reactants)* (See Table 17.4) |
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