Thermodynamics Flashcards
Zeroth Law of Thermodynamics
if object 1 is in thermal equilibrium with object 2
and object 2 is in thermal equilibrium with object 3
then object 1 and object 3 are in thermal equilibrium and there will be no net heat flow
Temperature
proportional to the avg kinetic energy of the particles that make up the substance
Heat
transfer of thermal energy from an object with higher temp(energy) to an object with lower temp (energy)
Thermal Equilibrium
if there is no net heat flow between two objects in thermal contact, then their temperatures are the same
F,C, K of Absolute Zero
-460
-273
0
F,C, K of Freezing Point Water
32
0
273
F,C, K of Boiling Point Water
212
100
373
Absolute Zero
theoretical temperature at which there is no thermal energy
Third Law of Thermodynamics
entropy of a perfectly organized crystal at absolute zero is 0
Fahrenheit, Celsius and Kelvin Equations
F = 9/5 C + 32
K = 273 + C
Physical properties of matter that change as a function of temperature
Length, volume, solubility and conductivity
Thermal Expansion of Matter: Length
delta L = alpha * L * delta T
alpha = coefficient of linear expansion
as temp goes up, length increases
as temp goes down, length decreases
Thermal Expansion of Matter: Volume Expansion
delta V = beta * V * delta T
beta = coefficient of volumetric expansion
Relation between Coefficient of Volumetric Expansion (beta) and Linear Expansion (alpha(
B = 3 * alpha
Isolated Systems
not capable of exchanging energy or matter with their surroundings ; total change in internal energy must be zero
very rare: examples are bomb calorimeter and the entire universe
Closed Systems
capable of exchanging energy, but not matter, with the surroundings
gases in vessels with movable pistons
Open Systems
exchange both matter and energy with the environment
matter carries energy but can be transferred via heat/work
boiling pot of water, humans, unconstrained combustion’s
State Functions
thermodynamic properties that are a function of equilibrium state of a system ; aka independent of the path taken to reach equilibrium
pressure, density, temperature, volume, enthalpy, internal energy, gibbs free energy, entropy
Process Functions
work and heat
describe the path taken to get from one state to another
First Law of Thermodynamics
change in total internal energy of a system is equal to the amount of energy transferred in the form of heat to the system minus the amount of energy transferred from the system in the form of work
deltaU = Q - W
deltaU = Q - W
U = change in systems internal energy
Q = heat flow into system
W = work done by the system
+ = increasing temp, heat flow into system, work done by the system (expansion)
- = decreasing temp, heat flow out of system, work is done on the system
Second Law of Thermodynamics
objects in thermal contact, but not thermal equilibrium will exchange heat energy going from high temp to lower temp until they have the same temperature at thermal equilibrium
Conduction
direct transfer of energy from molecule to molecule through molecular collisions (physical contact)
metals are good because they have a density of atoms in a sea of electrons while gases are bad because atoms have space between them
Convection
transfer of heat by physical motion of a fluid over a material
only liquids/gases apply
if fluid has a higher temperature, it will transfer energy to the material
Radiation
transfer of eneergy via electromagnetic waves
unlike the other two forms, can transfer energy through a vacumn
When heat energy is added/removed from a system, the temperature of that system will change in proportion to the amount of heat transfer, unless the system is undergoing ______ during which the temperature is ____
phase change
constant
Specific Heat (c)
amount of heat energy required to raise one gram of a substance by one degree C/K
changes according to its phase
1 cal/gK for water (need to know this)
Heat Gained/lost Equation
q=mc deltaT
c = specific heat of the substance
Phase change occurs at _____ temperature and the temperature will not begin to change until _____ has been converted from one phase into the other.
constant
all of the substance
Phase changes are related to changes in _____ energy, not ____ energy.
potential
kinetic
While liquid water may have a greater number of ______ due to increased freedom of movement, its avg kinetic energy is the ____ as solid water at the same temperature.
microstates
same
Microstates Ex: Water
As a solid, the atoms are bound by hydrogen atoms to restrict movement, but there is kinetic energy of the atoms vibrating
When heated up, water molecules move away, breaking the H bonds to increase degrees of freedom and increasing potential energy
however, the normal vibration activity also decreases as there are more methods of moving now
When heat energy is added or removed from a system experiencing phase change, _____ cannot be used to calculate heat added as there is no temperature change.
Instead, ______ is used where L is ______
q=mcdelta T
q=mL
heat of transformation/latent heat
Liquid to Solid Phase Change is called
freezing/solidification
Solid to Liquid phase change is called
melting/fusion
Liquid to Gas phase change is called
boiling, evaporation, vaporization
Gas to Liquid phase change is called
condensation
Isothermal
a process where Q = W
work = heat flow
delta U = 0 so constant temperature
Adiabatic
delta U = -W
delta U = change in systems internal energy
W = work
Q = 0 = heat flow so no heat flow
Isobaric
constant pressure
Isovolumetric /Isochoric
W = 0 so no work
deltaU = Q
Energy Dispersion
energy goes from being localized to being spread out/disperesed
Entropy
measure of the spontaneous dispersal of energy at a specific temperature
The larger the number of ______ energy can be spread out over, the higher the ___.
microstates
entropy
Change In Entropy Equation
delta S = Qrev / T
Qrev = heat gained/lost in reversible process
T = temp in kelvin
J/mol*k
When energy is distributed into a system at a given temperature, its entropy ____ . When energy is distributed out of a system at a given temperature, its entropy _____
increaes.
decreases
When energy is distributed into a system at a given temperature, its entropy ____ . When energy is distributed out of a system at a given temperature, its entropy _____
increase.
decreases
