TOPIC 12- SPONTANEITY, ENTROPY, AND FREE ENERGY Flashcards
A process is said to be ——- if it occurs without outside
intervention. Spontaneous processes may be fast or slow.
spontaneous
An alternative way to describe a spontaneous process
thermodynamically favored
Nature spontaneously proceeds toward the states that have the
highest probability of existing
The driving force for a spontaneous process is an increase in the
entropy
When order increases,
entropy decreases
inversely proportional
It is a measure of molecular randomness or disorder.
entropy
is a thermodynamic function that describes the number of
arrangements that are available to a system existing in a state.
Entropy
is each configuration that gives a particular arrangement.
microstate
Entropy changes in the surroundings are primarily determined by
heat flow
Solids, for example, are more ordered than liquids or gases and thus
have —— entropy.
lower
When a substance changes phase, entropy?
increases or decreases
It states that in any spontaneous process there is always an increase in the entropy of the universe.
The total energy of the universe is constant, but the entropy is increas
The Second Law of Thermodynamics
If Δ𝑆 universe > 0, the process is
spontaneous
The Δ𝑆 will be greater at ———— because there is 𝑠𝑢𝑟𝑟
less thermal energy to give.
lower temperatures
Entropy of the surroundings increases in an
exothermic process
is the entropy change for a reaction carried out at 1 atm and 25°C.
standard entropy of reaction (𝑆°𝑟𝑥𝑛)
If there are more gas molecules in the products,
Δ𝑆° > 0
If there are more gas molecules in the reactants,
Δ𝑆° > 0
If there is no net change in the total number of gas molecules, then Δ𝑆°
may be positive or negative but will be a
smaller number
is the amount of energy available to do work.
Free energy
If Δ𝐺 is negative, the process is
spontaneous
If Δ𝐺 is positive, the process is
nonspontaneous
If Δ𝐺 = 0, the process is in
equilibrium
is the change in free energy
that will occur if the reactants in their standard states are converted to the products in their standard states.
Standard Free Energy Change
Its value tells us nothing about the rate of a reaction, only its eventual
equilibrium position.
Standard Free Energy
It states that a perfect crystal represents the lowest possible entropy; that is, the entropy of a perfect crystal at zero Kelvin is zero.
The Third Law of Thermdynamics
If Δ𝐺 is negative, then K>1, and equilibrium shifts to the
right
If Δ𝐺 is positive, then K<1, and equilibrium shifts to the`
left
If Δ𝐺 is zero, then K=1, and ther will be
no shift
