Flashcards
Definitions Thermal physics
Flashcards do conjunto (33)
- 1Elementmaterial made up of just one type of atom
- 2Moleculecontains more than one type of atom
- 3Compoundsmaterials made from molecules
- 4Gasno fixed shape or volume. (ideally) no force between molecules
- 5Liquidno fixed shape but fixed volume. force between molecules not so strong so molecules can move around
- 6Solidfixed shape and volume. molecules held in position by a force, vibrate but don't move around
- 7Temperature (T)a measure of how hot or cold an object is. it is temperature that determines the direction of heat flow
- 8Celsius --> Kelvinadd 273
- 9Kelvin --> Celsiussubtract 273
- 10Thermal capacity (C)the amount of heat needed to raise its (somethings) temperature by 1*C. (J*C^-1) C=Q/(change in)T, where Q is quantity of heat
- 11Specific heat capacity (c)the amount of heat required to raise the temperature of 1kg of the material by 1*C. (unit: J kg^-1 *C^-1). c=Q/m(change in)T
- 12Boilingtakes place throughout the liquid and always at the same temperature
- 13Evaporationtakes place only at the surface of the liquid and can happen at all temperatures
- 14Specific latent heat (L)amount of heat required to change the state of 1kg of the material without change of temperature. L=Q/m (unit: J kg^-1) (latent = hidden)
- 15Energy suppliedpower x time
- 16The ideal gasmade up of a large number of perfectly ELASTIC, (IDENTICAL) TINY SPHERES moving in random motion. there are no forces between molecules (except when they collide);they move with constant velocity between collisions
- 17Pressureforce/area
- 18Equation of state for an ideal gasPV=nRT. P(ressure), V(olume), n(umber of moles), R (molar gas constant(booklet)), T(emperature)
- 19Isobaricconstant pressure
- 20Isochoricconstant volume
- 21Isothermalconstant temperature
- 22Internal energythe sum of all the KE of all the molecules
- 23Work donework is done when the point of application of a force moves in the direction of the force. force exerted on piston = PxA. work done when piston is moved (change in) d(istance), work done=PxAx(change in)d -> Ax(change in)d=change in volume V -> work done = Px(change in)V
- 24Sign of work+ when a gas does work it is pushing the piston out = positive.
- if work is done on the gas then something must be pushing the piston in = negative - 25First law of thermodynamicssimple version; if a gas expands and gets hot, heat must have been added. according to the law of conservation of energy; Q=(change in)U+W. (Q- amount of heat (change in)U - internal energy, W - work done by gas)
- 26Using P(ressure)V(olume) diagrams~change in VOLUME tells us whether work is done by the gas or on it. ~change in TEMPERATURE tells us whether the internal energy goes up or down. ~change in pressure is not interesting...
- 27Adiabatic contractionan adiabatic transformation is one where no heat is exchanged (Q=0). steeper than a "normal" temperature curve. first law of thermodynamics; Q=(change in)U+W -> 0=(change in)U+W -> (change in)U=W
- 28Net work done (thermodynamic cycles)the net work done during a (thermodynamic) cycle is the difference between the work done BY the gas and the work done ON the gas. this is equal to the area enclosed by the cycle on a PV diagram
- 29Thermodynamic cycleisochoric and isobaric changes. (volume and pressure)
- 30The Carnot cycleisothermal and adiabatic changes. (temperature)
- 31The second law of thermodynamicsit is not possible to convert heat completely into work. (since energy always spreads out)
- 32Entropyabout the spreading out of energy. ~entropy is a measure of how spread out or disordered the energy has become. ~saying entropy has increased implies that the energy has become more spread out. (change of)S=Q/T, unit: J K^-1. S=entropy, Q=quantity of heat, T=temperature
- 33Second law of thermodynamics in terms of ENTROPYin any thermodynamic process, the total entropy ALWAYS increases
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- Physics (Thermal physics) FlashCards sobre Definitions Thermal physics, criado por Moa Lindström em 05-04-2014.
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- Moa Lindström
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