Term
| In what direction does heat flow? |
|
Definition
| heat always flows from a warmer object to a cooler object. |
|
|
Term
| What happens in endothermic and exothermic processes? |
|
Definition
| in an endothermic process, the system gains heat as the surroundings cool down. in an exothermic process, the system loses heat as the surroundings heat up. |
|
|
Term
| In what units is heat flow measured? |
|
Definition
| heat flow is measured in two common units, the calorie and the joule. |
|
|
Term
| On what two factors does the heat capacity of an object depend? |
|
Definition
| the heat capacity of an object depends on both its mass and its chemical composition. |
|
|
Term
|
Definition
| the study of energy changes that occur during chemical reactions and changes in state. |
|
|
Term
| Chemical potential energy |
|
Definition
| the energy stored in the chemical bonds of a substance. |
|
|
Term
|
Definition
| energy that transfers from one object to another because of a temperature difference between them. |
|
|
Term
|
Definition
| the part of the universe on which you focus your attention. |
|
|
Term
|
Definition
| include everything else in the universe. |
|
|
Term
| Law of conservation of energy |
|
Definition
| states that in any chemical or physical process, energy is neither created nor destroyed. |
|
|
Term
|
Definition
| one that absorbs heat from the surroundings. |
|
|
Term
|
Definition
| one that releases heat to its surroundings. |
|
|
Term
|
Definition
| the amount of heat needed to increase the temperature of an object exactly 1 degree C. |
|
|
Term
|
Definition
| the amount of heat it takes to raise the temperature of 1g of the substance 1 degree C. |
|
|
Term
| What basic concepts apply to calorimetry? |
|
Definition
| in calorimetry, the heat released by the system is equal to the heat absorbed by its surroundings. Conversely, the heat absorbed by a system is equal to the heat released by its surroundings. |
|
|
Term
| How can you express the enthalpy change for a reaction in a chemical equation? |
|
Definition
| in a chemical equation, the enthalpy change for the reaction can be written as either a reactant or a product. |
|
|
Term
|
Definition
| the precise measurement of the heat flow into or our of a system for chemical and physical processes. |
|
|
Term
|
Definition
| the insulated device used to measure the absorption or release of heat in chemical or physical processes. |
|
|
Term
|
Definition
| the heat content of a system at constant pressure. |
|
|
Term
|
Definition
| a chemical equation that includes the enthalpy change. |
|
|
Term
|
Definition
| the enthalpy change for the chemical equation exactly as it is written. |
|
|
Term
|
Definition
| the heat of reaction for the complete burning of one mole of a substance. |
|
|
Term
| How does the quantity of heat absorbed by a melting solid compare to the quantity of heat released when the liquid solidifies? |
|
Definition
| the quantity of heat absorbed by a melting solid is exactly the same as the quantity of heat released when the liquid solidifies; that is, delta Hfus = -delta Hsolid. |
|
|
Term
| How does the quantity of heat absorbed by a vaporizing liquid compare to the quantity of heat released when the vapor condenses? |
|
Definition
| the quantity of heat absorbed by a vaporizing liquid is exactly the same as the quantity of heat released when the vapor condenses; that is, delta Hvap = -delta Hcond. |
|
|
Term
| What thermochemical changes can occur when a solution forms? |
|
Definition
| during the formation of a solution, heat is either released or absorbed. |
|
|
Term
| Molar heat of fusion (delta Hfus) |
|
Definition
| the heat absorbed by one mole of a solid substance as it melts to a liquid at a constant temperature. |
|
|
Term
| Molar heat of solidification (delta Hsolid) |
|
Definition
| the heat lost whem one mole of a liquid solidifies at a constant temperature. |
|
|
Term
| Molar heat of vaporization (delta Hvap) |
|
Definition
| the amount of heat necessary to vaporize one mole of a given liquid. |
|
|
Term
| Molar heat of condensation (delta Hcond) |
|
Definition
| the amount of heat released when one mole of vapor condenses at the normal boiling point. |
|
|
Term
| Molar heat of solution (delta Hsoln) |
|
Definition
| the enthalpy change caused by dissolution of one mole of substance. |
|
|
Term
| What are two ways that you can determine the heat of reaction when it cannot be directly measured? |
|
Definition
| Hess's law allows you to determine the heat of a reaction indirectly. |
|
|
Term
| Hess's law of heat summation |
|
Definition
| states that if you add two or more thermochemical equations to give a final equation, then you can also add the heats of reaction to give the final heat of reaction. |
|
|
Term
| Standard heat of formation (delta Hf^0) |
|
Definition
| the change in enthalpy that accompanies the formation of one mole of a compound from its elements with all substances in their standard states at 25 degrees C. (delta Hf^0=0) |
|
|
