Thermodynamics Flashcards
zeroth law of thermodynamics
transitive properties in thermal systems: if a=b and b=c, then a=c
temperature
physical property based on the average kinetic energy of its particles
heat
transfer of thermal energy from a hotter object with higher temperature to a colder object with lower temperature
thermal equilibrium
if no heat flows between two objects
absolute zero
theoretical temperature at which there is no thermal energy
third law of thermodynamics
entropy of a perfectly-organized crystal at absolute zero is zero
temperature conversions
F=(9/5)C+32
K=C+273
linear thermal expansion equation
ΔL=αLΔT
where L is length and alpha is coefficient of linear expansion
volume thermal expansion equation
ΔV=βVΔT
where B is the coefficient of volumetric expansion
isolated systems
not capable of exchanging energy or matter with their surroundings
closed systems
capable of exchanging energy, but not matter, with their surroundings
open system
exchange both matter and energy with the environment
state function
thermodynamic properties that are a function of only the current equilibrium state of a system
-pressure, density, temperature, volume, enthalpy, internal energy, Gibbs free energy and entropy
process functions
describe the path taken to get from one state to another; work and heat
first law of thermodynamics
states that the change in the total internal energy of a system is equal to the amount of energy transferred in the form of heat to the system, minus the amount of energy transferred from the system in the from of work
change of internal energy
ΔU=Q-W
Where U is the change in the systems internal energy, Q is the energy transferred into the system as heat and W is the work done by the system
second law of thermodynamics
objects in thermal contact and not in thermal equilibrium will exchange heat energy such that the object with a higher temperature will give off heat energy to the object with lower temperature until they are in equilibrium
heat conversion
1 Cal=10^3cal=4184 J=3.97 BTU
conduction
direct transfer of energy from molecule to molecule through molecular collisions
convection
transfer of heat by the physical motion of a fluid over material; only liquid and gases
radiation
transfer of energy by electromagnetic waves
specific heat
amount of heat energy required to raise one gram of the substance by one degree
water specific heat
1 cal/g*K
heat gain/loss equation
q=mcΔT
m=mass
c=specific heat
T=temperature change
heat energy during phase change
q=mL
q is the amount of heat gained or lost
m is the mass
L is heat of transformation or latent heat
isothermal process
constant temperature
adiabatic process
no heat exchange
isovolumetric/isochoric process
no change in volume
isobaric process
occur at a constant pressure
entropy
measure of the spontaneous dispersal of energy at a specific temperature
entropy equation
ΔS=Q/T
S=change in entropy
Q=heat gained or lost in a reversible process
T=temperature in kelvin
