cram thermodynamics Flashcards
isolated system
no exchange with environment
closed system
energy exchange with environment
open system
exchange of matter and energy with environment
adiabatic
no exchange of heat
termos, stanely cup
macroscopic characterization of a thermodynamic system
determines the state of the system by state variables
p, V and T are state variables if they describe a system in equillibrium state
extensive variables
depend on size of the system e.G energy, mass, volume, charge, entropy
intensive variables
do not depend on size e.g: pressure, temperature, concentration
equillibrium
can be reasched by spontaneous process without any outside intervention
- properties of system do not change with time
- intensive variables are uniformely distributed througout the system
non-equillibrium
may contain intensice variables which vary in space and time
internal energy
the energy an object or substance is due to the molecular kinetic and potential energies associated with the random motions of all the particles that make it up
kinetic energy
due to motion of the particles
potential energy
due to interactions between the atoms, ions and molecules
ideal gas with one atom
translational energy
ideal gas with several atomsq
translational and rotational and vibration energy
liquid and solid body
translational, rotational, vibration energy and attractive molecular interactions
elementary energy exchanges
W = y *dx
W = y * dx
extensive (x)
volume, matter, charge
intensive (y)
pressure
chemical potential
electric potential
temperature
product:
volumetric work
work of material transport
heat
change of internal energy
sum of individual energy exchanges
thermal interactions - > DeltaQ
dQ=TdS
first law of thermodynamics
law of conservation of energy. energy may be converted into different forms, but the total energy of the system remains constant
latent heat
Latent heat is thermal energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. Found between change of states (from solid to liquid)
equalization of temperature and/or pressure leads to
increase in entropy
entropy in equillibrium is
constant
real processes leading to equillibrium
1) temperature equalization
2) mixing of gases
3) conversion of macroscopic kinetic energy to thermal energy
second law of thermodynamics
during spontaneous processes entropy always increases. spontaneous processes proceed towards the most pronable state
entropy maximum
thermodynamic equillibrium
statistical entropy
s=k*lnOmega
omega is the thermodynamic probability. thermodynamic probability is gives the number of microstates for a given macrostate
high conformational entropy
random coil
small conformational entropy
ordered conformations
third law of thermodynamics
the entropy of one-component, crystallizing when temperature approaches zero
s=0 t=0 omega is 1
it is impossible to reach t in a finite number of steps
usable part of internal energy at constant pressure
enthalpy
H=U+pV
isobaric
usable part of internal energy at constant temperature
free energy
F = U-TS
