Chemical Thermodynamics Flashcards
It is a process that proceeds on
its own, without any outside
intervention.
spontaneous
The part of the universe being studied
or to which attention is focused.
system
Everything else in the
thermodynamic universe aside
from the system.
surroundings
Quantitative measure of the disorder
or randomness of a system.
entropy
is the study of the relationship between heat
and work involving chemical reactions or physical
changes in state, within the framework of the
laws of thermodynamics.
Chemical
Thermodynamics
A _______________ process is a
physical or chemical change
that occurs on its own without
any outside force.
spontaneous
A _________________ process will
not take place unless it is “driven”
by the continual input of energy
from an external source.
nonspontaneous
Spontaneous or Nonspontaneous
● Hot coffee turning cold
Spontaneous
Spontaneous or Nonspontaneous
● Rusting of iron
Spontaneous
Spontaneous or Nonspontaneous
● Water decomposes into hydrogen and oxygen
gases with application of electricity.
Nonspontaneous
Spontaneous or Nonspontaneous
● A spoon dipped in boiling water gets hot
Spontaneous
The quantitative measure of the disorder, or randomness, in the
substances involved in a reaction.
Entropy
Helps to predict the spontaneity of the process.
Entropy
Positive ΔS = ______________ in randomness
increase
Negative ΔS = ______________ in randomness
decrease
Perfectly ordered pure crystalline solid
at zero Kelvin will have _______ entropy
zero
FACTORS AFFECTING ENTROPY: TEMPERATURE
Change in temperature = _________ in entropy
Inc temperature = _________ entropy
change, increased
Predict the sign of the change in entropy of the ff:
POSITIVE OR NEGATIVE
Freezing of water
NEGATIVE
Predict the sign of the change in entropy of the ff:
POSITIVE OR NEGATIVE
Heating liquid water to its boiling point
POSITIVE
Predict the sign of the change in entropy of the ff:
POSITIVE OR NEGATIVE
Sublimation of naphthalene
POSITIVE
(Sublimation = Solid to Gas)
(Deposition = Gas to Solid)
Solid = Less randomness
Gas = More randomness
Reactions that produce
higher number of product
particles than reactant
particles are usually
_________________
spontaneous
More particles = more ____________
disordered
Is the entropy of one
mole of a substance at
the standard conditions
(1 atm and 25°C).
Standard molar entropy (S°)
What Law?
“For any spontaneous process, there is a net increase in
the total entropy of the system and its surroundings.”
SECOND LAW OF THERMODYNAMICS
the equation for a reaction occurring
at constant temperature expressed as:
ΔG = ΔH - TΔS
Gibss-Helmholtz
Under standard conditions of 1 atm and 25
°C, the standard free energy change (ΔG°) can
be obtained through:
ΔG° = ΔH° - TΔS°
Gibbs Free Energy (G)
The standard free energy change of a reaction
can also be calculated from the standard free
energy of formation (ΔG°f) of the __________
and _____________:
reactants, products
ΔG is negative, the reaction is _________________
spontaneous
ΔG is positive, the reaction is ___________________
nonspontaneous
ΔG is zero, the reaction is _____________.
at equilibrium
