| Term | Definition |
|---|
| Brownian Motion | The atoms of any substance are continually in motion; supports atomic theory |
| Mole | number of grams which is numerically equal to the atomic or molecular mass |
| Avogadro's number | 6.02 x 10^23; the number of atoms or molecules in 1 mol of any pure substance |
| Temperature | measure of how hot or cold something is |
| Thermometer | used to measure temperature |
| Thermal equilibrium | when objects at different temperatures are placed in thermal contact, they will reach the same temp |
| Equation of state | volume of gas depends on pressure and temp, V, T, m, P |
| Equilibrium state | when variables of a system are not changing |
| ideal gas | PV = nRT |
| Postulate of Kinetic Theory | 1) large number of molecules, N, moving randomly w/variety of speeds- gas fills container; 2) molecules are far apart relative to their diameter; 3) molecules interact only when they collide, PE is small compared to KE b/c attractions are weak, so we ignore it; 4) elastic collisions |
| calorie | the amount of heat necessary to raise the temp of 1 gram of water by 1 Celsius degree |
| kilocalorie | the heat needed to raise 1 kg of water by 1 Celsius degree |
| Calorie | kilocalorie; by this, energy value is specified |
| Joule | N x m; unit |
| heat | energy transferred from one object to another b/c of a difference in temperature |
| Mechanical equivalent of heat | says 4.186J = 1cal, 4.186 kJ = 1kcal |
| Internal energy | sum total of all the energy of all the molecules in an object |
| specific heat | c; quantity characteristic of the material |
| closed system | a system for which no mass enters or leaves |
| open system | mass may enter or leave the system |
| isolated | if no energy in any form passes across the boundaries of a closed system |
| calorimeter | measures heat exchange |
| colorimeter | measures color |
| change of phase | solid to liquid or liquid to gas |
| heat of fusion | the heat required to change 1 kg of a substance from solid to liquid |
| heat of vaporization | the heat required to change 1 kg of a substance from liquid to gas |
| latent heat | values of the heats of fusion and vaporization |
| calorimetry | the quantitative measurement of heat exchange |
| conduction | heat through molecular collisions |
| thermal conductivity | characteristic of a material |
| conductors | substances for which k is large conduct heat rapidly |
| insulators | where k is small are poor conductors of heat |
| convection | process whereby heat flows by the mass movement of molecules from one place to another |
| radiation | the transfer of heat by the sun over empty space; elctromagnetic waves |
| emissivity | e; number between 0 and 1 that is characteristic of the surface of the radiating material |
| Thermodynamics | the study of processes in which energy is transferred as heat and as work |
| system | any object/set of objects that we wish to consider |
| 1st law of thermodynamics | heat added is +, heat lost is -, work on system is -, work by system is +; conservation of energy |
| state variables | quantities which describe the state of a system |
| heat reservoir | a body whose mass is so large that, ideally, its temperature d/n change significatly when heat is exchanged w/our system |
| 2nd law of thermodynamics | says which processes occur in nature and which do not; heat can flow spontaneously from a hot object to a cold object; heat will not flow spontaneously from a cold object to a hot object |
| heat engine | any device that changes thermal energy into mechanical work (steam engines and automobile engines) |
| isobaric | process in which pressure is constant |
| isochoric | process in which volume is constant |
| adiabatic | no heat flows in or out of the system |
| isothermal | constant temperature in a process |
| isovolumetric | same as isochoric |
| operating temperatures | high and low temperatures |
| working substance | the material that is heated and cooled |
| Carnot engine | an ideal engine examined by Sadi Carnot |
| reversibly | processes done slowly so that the process could be considered a series of equilibrium states and could be done in reverse with no changes |
| irreversible | real processes cannot be done in reverse; therefore they are ____ |
| coefficient of performance | heat QL removed from the low-temp area inside a refrigerator divided by the work W to remove the heat |
| entropy | a function of the state of a system, unlike heat; time's arrow |
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