Studied by 1 personkinetic energy
-energy that something has because it is moving
Kinetic energy depends on a particle's...
mass and velocity
translation
3D movement of particles
movement of particles in a solid
vibration or rotation
potential energy
energy something has as a result of its position
types of potential energy
structural or positional
examples of potential energy
gravitational, electrostatic, chemical bond energy
-E =
q+w
internal energy
sum of all the individual energies of nanoscale particles in a system
internal energy depends on...
temperature, type, and number of particles
higher T =
higher energy
Joule
1 kg m^2/s^2
calorie
original energy unit, 4.184 J
calorie definition
energy required to heat one gram of water one degree celsius
system
the region of the universe we are studying
surroundings
everything else, separated from the system by a boundary
open system
exchanges both energy and matter with the surroundings
closed system
exchanges energy but mot matter with the surroundings
isolated system
neither energy nor matter is exchanged between the system and surroundings
open system example
a glass of soda
closed system example
a unopened can of soda
isolated system example
capped thermos bottle
equation for calculating thermodynamic change
deltaE = Efinal -Einitial
state variable
depends only on the state of the system and is independent of how it got there
path variable
depends on how the state was reached
heat (q)
the energy associated with the translation, rotation, and vibration of molecules
magnitude of delta T depends on...
q
molar heat capacity (C)
accounts for the identity of a material and is intrinsic
molar heat capacity synonym
heat capacity
heat capacity equation
C=q/n deltaT
specific heat capacity
quantity of heat required to raise the temperature of one gram of a substance by one degree K
specific heat synonym
specific heat
work (w)
energy used to move an object against an opposing force
work=
force x displacement
work units
N*m
expansion work
w= -Pext x deltaVsystem
First Law of thermodynamics
deltaEsys = qsys + wsys qsurrounding = -qsystem
automobile engine
some heat is lost while doing expansion work
automobile engine equation
deltaEstove = qengine + wengine
gas stove
all energy is converted into heat
gas stove equation
deltaEstove = qstove
calorimetry
device that measures heat flow in a chemical reaction
calorimetry equation
qsys = qcalorimeter + qchemical = 0
constant pressure calorimeter
-most common way to measure heat flow -used in most labs -explains biological systems -open system
constant volume calorimeter
-bomb calorimeter used to counteract large pressure increase -closed system
enthalpy equation
H = E + PV deltaH = deltaE + PdeltaV
heat of formation
heat required to produce of a single product from standard elements in standard condition
Hess's Law
the enthalpy change for any process s the sum of the enthalpy changes for any set of steps leading up to it
enthalpy is related to
intermolecular force strength
lattice energy
the energy required to separate one mole of an ionic solid
exothermic reactions tend to favor
products
free energy
energy we can use to do work
energy is more likely to spread...
over many particles rather than a few
entropy
a measure of dispersed energy of a system
how can we disperse energy/matter?
spread something into a larger volume or allow two items to reach thermal equilibrium
mixing of miscible substances
spontaneous
most probable mixing pattern of particles
has the most uniform distribution of particles thru the volume the particles occupy
W
number of energy equivalent arrangements of particles
entropy is proportional to...
number of possible arrangements
Boltzmann equation for entropy
S = k ln(W)
accessible microstates
probable number of arrangements of particles at a particular T
third law of thermodynamics
entropy of a pure, perfect crystal is zero at O K
standard molar entropy
entropy of one mole of a substance at P= 1 barr and T=25 C
which phase of matter has the greatest entropy
gases
quantum theory of entropy
energy levels for gas motion get closer together when the volume expands, more energy levels become accessible at a given T, E will disperse more over these levels
when a processes product favored?
when energy is dispersed from few to many levels
Carnot entropy equation
S= Sf-Si = qrev/T
reversible process
can be reversed by a slight change in condition
entropy of solids
very small as particles are essentially fixed
entropy of liquids
moderate entropy as particles slide past eachother
entropy of gases
large entropy as particles move freely
Factors that increase entropy
-greater motion -greater complexity -weaker ionic force -large matter dispersal -particle mass -temperature -dissolution
entropy of aqueous solutions
tends to be large as it allows for a greater dispersion of ions
less condensed phase is always...
more favorable
spontaneous process
-occurs naturally under certain conditions -can be instantaneous or slow
nonspontaneous process
driven by a continual input of energy from an external source
thermodynamics
study of relationships between the energy and work associated with chemical and physical properties
spontaneous processes often result in...
greater dispersal of energy or matter
microstates
special configuration of all the locations and energies of the atoms or molecules in a system
increase of microstates with number of particles
exponential
second law of thermodynamics
all spontaneous changes cause an increase in the entropy of the universe
second law of thermodynamics equation
deltaSuniv = deltaSsys + deltaSsurr
standard entropy change
the total entropy of the products - the total entropy of the reactants
the total entropy of the universe is continuously...
increasing
standard entropy of surroundings =
-deltaH of the system/T
Gibbs free energy
combines S and H to predict spontaneity
Gibbs energy equation
G = H - TS (or changes of)
delta G < 0
free energy decreases; product favored
delta G > 0
free energy increases, reactant favored
gibbs free energy of formation equation
G = sum(nGproducts) - sum(nGreactants)
free energy of a system during a reaction
continuosly decreasing
G = 0
reaction has reached its most stable state (equilibrium)
H-, S+
product favored at all T
H-, S-
product favored at low T
H+, S+
product favored at high T
H+, S-
not product favored
when is the free energy greatest?
when only the reactants are present
delta G = wsys =
-wmax
3 steps of extracting free energy from nutrients
digestion, conversion of enzymes to acetyl coenzyme A, citric acid cycle
digestion
large molecules are broken down into smaller ones
Note
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