Chapter 3 Flashcards
A spontaneous change occurs
___________ continuous input of
energy into the system from
outside
without
A nonspontaneous process
requires_________ input of
energy
constant
Spontaneous in one direction
means ____________ in
opposite direction
non-spontaneous
_______________ processes involve ordered motion becoming
random and localized energy becoming dispersed
Spontaneous (Non-spontaneous processes involve the reverse)
Thus, dispersal of matter and energy tends to be
______________ while the concentration of matter
and energy tends to be non-spontaneous
spontaneous
Second Law of Thermodynamics
Heat does not flow spontaneously
from a cool body to a hotter body
The Second Law can be expressed in terms of a new state function, _____________
entropy
The entropy of an isolated system __________ in the course of a spontaneous change: ΞStot > 0
increases
Thermodynamically irreversible changes always have ______________
ΞStot > 0
define entropy in thermodynamics
according to the what equation?
ππ = πππππ£/T & βπ = Χ¬π
π πππππ£/T
In some processes, ΞSsys is negative (energy or matter is getting concentrated, not dispersing) but can still be spontaneous if _______________
spontaneously if ΞSsur is sufficiently positive that ΞStot > 0
What are some examples of spontaneous processes where ΞSsys is positive?
Gas expanding
β Water evaporating
What are some examples of spontaneous processes where ΞSsys is negative?
-Water condensing on a cold glass
β Water freezing from a liquid to a solid in the freeze
So, πππππ£/π is essentially the _______________ value for the change in entropy for a process; it could be more
minimum
units of entropy are
what?
J/K
Entropy is an ____________ property, so amount of entropy depends on system size
extensive
What is the equation used for entropy and the surrounding?
βππ π’π = ππ π’π/ T sur
we generally assume that the
surroundings are held at a __________ temperature and either constant volume or constant pressure
constant
what is βππ π’π for an adiabatic
process?
βππ π’π = 0
In statistical mechanics, entropy is defined via the Boltzmann equation as what?
π = π ln π² & π = π ln Ξ© (where π² or Ξ© represent the number of microstates possessed by a state with a given internal energy. k is
the Boltzmann constant: k = 1.380649Γ10β23 Jβ
Kβ)
microstate
snapshot of a state at the molecular level
A microstate is described by the individual positions and ________________ of every atom
velocities
There are generally huge numbers of ____________ microstates β microstates with the same values of the macroscopic variables P, V, T, and n
equivalent
Less constrained systems (like gases) have ________ equivalent microstates
more