# Shared Flashcard Set

## Details

Thermo1
key words and formulas
41
Physics
09/18/2010

Term
 Intensive
Definition
 independent of size of system i.e. T, P, or density
Term
 Extensive
Definition
 depend on size/extent of system i.e. m, V, E
Term
 Equilibrium
Definition
 implies a balance i.e. no unbalanced driving forces
Term
 quasi-equilibrium (QE) process
Definition
 When process proceeds so that the system remains infinitesimally close to an equilibrium state at all times,
Term
 isothermal
Definition
 Constant Temperature
Term
 isobaric
Definition
 Constant Pressure
Term
 isochoric
Definition
 Constant volume
Term
 cycle
Definition
 if a system returns to its initial state at end of process i.e. initial and final states of cycle are same
Term
 dimensions
Definition
 Physical quantities characterized (mass, m, or velocity, V, etc.)
Term
 primary or fundamental dimensions
Definition
 Basic dimension mass m, length L, time t, temperature T
Term
 secondary or derived dimensions
Definition
 velocity V, energy E, volume V expressed in terms of primary dimensions
Term
 Kinetic energy
Definition
 due to system motion w/rt reference frameKE = mV2/2 (kJ)
Term
 Potential energy
Definition
 due to system elevation in gravitational fieldPE=mgz (kJ)
Term
 Total energy and specific total energy
Definition
 E = U + KE + PE + U + (mV^2)/2 + mgz
Term
 Heat transfer
Definition
 Heat is a form of energy that is transferred between a system and its surroundings by virtue of a temperature difference in a direction of higher T to lower THeat is energy in transition and is only recognized as it crosses the boundaryHeat is form of energy so units are kJ or Btu (1 kJ=0.94782 Btu)
Term
 Heat transfer sign convention
Definition
 Q > 0: heat transfer to the systemQ < 0: heat transfer from the systemQ = 0: adiabatic
Term
 Heat transfer by 3 modes
Definition
 1) conduction (solid/fluid; molecular collision) ~derivative of T2) convection (fluid; motion) ~ T difference3) radiation (no medium needed/wave vs. particle) ~ T^4
Term
 Work
Definition
 work involves a force acting through a distanceExamples include a rising piston, rotating shaft, current carrying wire, etc
Term
 Work Sign convection
Definition
 W < 0 is work done on the system W > 0 is work done by the system
Term
 First Law of Thermodynamics
Definition
 deltaE = Q -WQ - W = deltaE + dektaU + deltaKE + deltaPEQ - W = deltaU (stationary system)Q - W = 0 (cyclic process)
Term
 Phase
Definition
 refers to quantity of matter that has same chemical composition and physical structure throughout e.g. all solid, all liquid, or all vapor (gas)
Term
 pure substance
Definition
 with fixed chemical composition throughout i.e. water, N2, He, CO2, etc.
Term
 Solid (Phase)
Definition
 molecules are closely packed and arranged in a 3D pattern (lattice) which is repeated throughout solid e.g. long range order
Term
 Liquid (Phase)
Definition
 chunks of molecules float about each other but w/in each chunk molecules maintain orderly structure e.g. short range orderDefinite volume but fluid shapeSlight increase in distance between molecules over solid
Term
 Gas (Phase)
Definition
 molecules far apart w/ no molecular orderMolecules move about at random colliding w/ each other and walls of containerShape and volume defined by container
Term
 compressed or subcooled liquid (CL or SL)
Definition
Term
 saturated liquid (SL)
Definition
 liquid about to boil (cant hold in any more heat)
Term
 Saturated liquid-vapor mixture (SLVM)
Definition
 under wet domeT = constant due to breaking of bonds
Term
 Saturated vapor (SV)
Definition
Term
 Superheated vapor (SHV)
Definition
Term
 Quality
Definition
 x = (m_vapor/m_total) m_total = m_vapor + m_liquid
Term
 SLVM property formula
Definition
 y = y_f + x (y_g - y_f)x = (y - y_f)/(y_g - y_f)y_f <= y <= y_g (inside wet dome)
Term
 Thermodynamic system
Definition
 quantity of matter *or* a region of space chosen for study
Term
 Surroundings
Definition
 Mass or region outside system
Term
 Boundary
Definition
 Real or imaginary surface that separates system from surroundings
Term
 Closed system
Definition
 Features:– Fixed amount of mass– No mass can cross its boundary– Energy (in form of heat and work interactions) can cross boundary– Volume of closed system does not haveto be fixed
Term
 Open system
Definition
 control volumeBoth mass and energy can cross the boundary of a CV
Term
 Property
Definition
 Any characteristic of a systemi.e. pressure P, temperature T, volume V, mass m, etc.
Term
 Specific Volume
Definition
 [image]
Term
 P-V-T Surface
Definition
 [image]
Term
 P-V T-V digram
Definition
 [image]
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