Thermodynamics Flashcards
Who coined the term “Thermodynamics”?
James Prescott Joule
Who is considered the Father of Thermodynamics?
Nicolas Sadi Carnot
Formula for Farenheit to Celcius
C = (5/9) (F - 32)
Formula for Celcius to Farenheit
F = (9/5)C + 32
A change in Celcius is ______ths of a change in Farenheit
5 / 9
Boiling point of Water IN FARENHEIT
212 F
The unit for temperature named after William Thomson
he is also known as ______________
Kelvin, Lord Kelvin :v
A change in Celcius is ________ a change in Kelvin
Equal to
Another absolute temperature scale other than Kelvin
Rankine
Formula for Rankine
R = F + 460
A change in Kelvin is ______ths of a change in Rankine
5 / 9
A change in Rankine is ________ a change in Farenheit
Equal to
Formula for Thermal Expansion
ΔL = α L ΔT
ΔL - change in length
α - Linear coefficient of thermal expansion
L - original Length
ΔT - Change in temperature
Linear coefficient of thermal expansion of Copper
18 x 10^-6 (in /C)
Formula for Areal Expansion
ΔA = γ A ΔT
ΔA - change in Area
γ - Areal coefficient of thermal expansion
A - original Area
ΔT - Change in temperature
Formula for Volumetric Expansion
ΔV) = β V ΔT
ΔV - change in Volume
β - Volumetric coefficient of thermal expansion
V - original Volume
ΔT - Change in temperature
Relation of Linear coefficient of thermal expansion(α) to Areal coefficient of thermal expansion(γ) and Volumetric coefficient of thermal expansion(β)
β= 3α γ = 2α
Defined as the Internal energy in transit from one body to another By virtue of a temperature difference between them
Heat
1 calorie is equivalent to how many joules?
4.186 J
1 BTU is equivalent to how many joules?
1054 J
1 BTU is equivalent to how many foot-pounds?
778 ft.lb
How much heat in calories is required to heat one gram of water by 1 Celcius?
1 Calorie
How much heat in BTU is required to heat one pound-mass of water by 1 Farenheit
1 BTU
A property of a material that defines how many calories or heat is required to raise a material’s Temperature by a specific amount, without considering the material’s mass
Heat Capacity
Formula of Heat that uses Heat Capacity as a variable
Q = C ΔT (unit in calories)
C-Heat capacity (in cal/Celcius)
Q-Heat in Calories
Defined as the Heat Capacity per unit mass
Specific Heat
The two variations of Specific Heat Capacity
Cp (Specific Heat @ Constant pressure)
Cv ( Specific Heat @ Constant Volume)
Formula for Molar Specific Heat
Cm = (MW)(c)
MW - Molar Weight
c - Specific Heat
Formula of heat, given mass and specific heat
Q = m (c) ΔT
Q - Sensible heat
m - mass of material
c - specific heat of material
Specific heat of water
1 cal/(g . C)
Specific Heat of Ice
0.5 cal/(g . C)
Specific Heat of Steam
0.45 cal/(g . C)
The Constant that relates Cp and Cv
Adiabatic Constant (γ)
Formula for Adiabatic Constant(γ)
γ = Cp / Cv
Adiabatic Constant for a monoatomic compound
γ = 1.67
Adiabatic Constant for a diatomic compound
γ= 1.4
Latent heat that involves change from solid to liquid and vice versa
Latent Heat of Fusion
Latent Heat of Fusion(L) in J/g
L = 333.5 J/g
Latent Heat of Fusion(L) in Cal/g
L = 80 Cal/g
Latent heat that involves change from Liquid to gas and vice versa
Latent Heat of Vaporization
Latent Heat of Vaporization(L) in J/g
L = 2256.7 J/g
Latent Heat of Vaporization(L) in cal/g
L = 540 cal/g
Latent heat that involves change from Gas to solid and vice versa
Latent Heat of Sublimation
Latent Heat of Sublimation(L) in J/g
L = 2838 J/g
Latent Heat of Sublimation(L) in cal/g
L = 670 cal/g
The heat required to perform phase(solid liquid gas) transformation
Heat of Transformation
Formula for Heat of Transformation(Q)
Q = m(L)
m - mass in grams
L - Latent Heat (Fusion, Sublimation, or Vaporization)
Formula for the rate of Heat transfer(Q/t)
AKA FOURIER’s LAW
(Q/t) = (k . A . ΔT) / L
k - Thermal Conductivity
A - Cross sectional area (m^2)
ΔT - difference in temperature between the two ends of the material wehre heat is transferred (in Kelvin)
L - Length of material (meters)
Formula for Thermal Resistance(R)
R = L / K
k - Thermal Conductivity
L - Length of material (meters)
Formula for the Temperature Gradient
Temp. Gradient = ΔT / L
The Property that measures the thermal insulating ability of a material
Thermal Resistance
Heat transfer that involves the flow of fluids or matter
Convection
Formula of Rate of Heat Transfer(Q/t) Due to Convection
Q/t = h . A . ΔT
h - convection Coefficient
A - Area in contact of convection
ΔT - Difference in temperature between two regions
Heat transfer that does not require a medium
Radiation
Stefan-Boltzmann Constant(sigma)
(sigma) = 5.68 x 10^-8 W / (m^2 . K^4)
Formula for Stefan-Boltzmann Law
AKA HEAT TRANSFER(Q/t) DUE TO RADIATION
Q/t = (sigma)(e)(A) . (T)^4
e = emissivity
A - Area of Coverage
(sigma) - Stefan-Boltzmann Constant
T - Temperature; if Temp. difference exists, replace T^4 with: (T2)^4 - (T1)^4
The ability to emit radiation
emissivity
emissivity(e) of the sun
1
emissivity(e) of a perfect reflector
0
emissivity(e) of a black body
1 Manacup….. jk lang,
Answer: 1
The formula that depicts the first law of thermodynamics
U = +-(Q) +-(W)
U - CHANGE in internal energy of system
Q - Heat absorbed/released by system
W - Work done on/by the system
Who coined the term “Energy”
Thomas Young
In Engineering convention, If heat is ABSORBED by the system, Q is (Positive/Negative)?
Positive
In Engineering convention, If heat is RELEASED by the system, Q is (Positive/Negative)?
Negative
In Engineering convention, If work is done ON the system, W is (Positive/Negative)?
Positive
In Engineering convention, If work is done BY the system, W is (Positive/Negative)?
Negative
The Interface that separates a system to its surroundings
Boundary
A system where matter enters and leaves at the same rate
Steady Flow System
A system where NOTHING crosses the boundary
Isolated System
A system where heat does not cross the boundary
Therefore ΔQ = 0
Adiabatic System
A system where heat MAY cross the boundary
Diathermic System
A system where Matter may not cross the boundary, but heat may cross
Closed System
Another term for Closed System
Control Mass System
A system where EVERYTHING can cross the Boundary
Open System
Another Term for Open System
Control Volume System
The fastest reaction in a Thermodynamic system
Adiabatic
In an adiabatic system, only ___________ contributes to a change in the internal energy of the system
work
Value of Cv of a monoatomic substance
Cv = 3R / 2
R - 8.314 J/k.mol
Value of Cp of a monoatomic substance
Cp = 5R/2
R - 8.314 J/k.mol
Value of Cv of a diatomic substance
Cv = 5R/2
R - 8.314 J/k.mol
Value of Cp of a diatomic substance
Cp = 7R/2
R - 8.314 J/k.mol
Formula that depicts relationship of Cv to Cp
Cp = Cv + R
R - 8.314 J/k.mol
Formula for Heat in an adiabatic process
Q = n(Cp OR Cv) . ΔT
n - number of moles
ΔT - Change in Temperature
Formula for Work in an adiabatic process
W = (1 / (γ - 1))[P2V2 - P1V1]
γ - adiabatic constant
Thermodynamic process where pressure is held constant
Isobaric
Thermodynamic process where Volume is held constant
Isochoric
Thermodynamic process where Temperature is held constant
Isothermal
Formula for Work in an Isobaric Process
W = -P . ΔV
P - Pressure
V - Volume
Formula for Heat in an Isobaric Process
Q = m Cp ΔT
m - mass
Cp - Specific heat when constant pressure
ΔT - Change in Temperature
In an Isothermal process, the energy in a system __________?
Remains the same (Change in energy is zero)
In an Isothermal process, What two properties of a system are the same in magnitude?
Heat and Work:
U = Q + W ; but in isothermal, U = 0
therefore, Q = -W
Formula for Work in an Isothermal process (Using Initial and Final Volume)
W = -nRT ln (V2 / V1)
n - # moles
R -8.314 J/k.mol
T - Temp. in Kelvin
Formula for Work in an Isothermal process (Using Initial and Final Pressure)
W = +nRT ln (P2 / P1)
n - # moles
R -8.314 J/k.mol
T - Temp. in Kelvin
The work in an Isochoric Process is equal to
since ΔV = 0,
W = -P . ΔV
W = 0
Change in internal energy is attributed only to ________ in an isochoric process
Answer: Heat
ΔU = Q + W
but W = 0
therefore, ΔU = Q
Formula for Heat in an Isochoric Process
Q = m Cv ΔT
m - mass
Cv - Specific heat when constant volume
ΔT - Change in Temperature
An adiabatic process in which there is no change in entropy (ΔS = 0)
Isentropic Process
An adiabatic Process that Throttles
Isenthalpic Process
The Change in Enthalphy in an Isenthalpic Process is ____________________
ΔH = 0
With Throttling, there is a significant drop in _________
Pressure
P2 < P1
When Gas is Throttled, the change in temperature over the change in pressure is called
Joule -Thomson Coefficient
All Thermodynamic processes are (Reversible/Irreversible)
Irreversible
Formula for Polytropic Process
P1 . (V1)^n = P2 . (V2)^n
n - Polytropic Exponent
If the Polytropic Exponent(n) is ZERO, the effect is that the process becomes a/an ___________ process
Isobaric
If the Polytropic Exponent(n) is ONE, the effect is that the process becomes a/an ___________ process
Isothermal
If the Polytropic Exponent(n) is INFINITY, the effect is that the process becomes a/an ___________ process
Isochoric
If the Polytropic Exponent(n) is the ADIABATIC CONSTANT, the effect is that the process becomes a/an ___________ process
Adiabatic
If the Polytropic Exponent(n) is K, the effect is that the process becomes a/an ___________ process
Isentropic
Note: idk what K is :v, maybe boltzmann
Formula for Polytropic Specific Heat
Cn = Cv . ( n - K ) / ( n - 1 )
n - polytropic exponent
Note: idk what K is :v, maybe boltzmann
2nd Law of Entropy
Entropy Increases as time approaches Infinity.
Entropy never increases
3rd Law of Entropy
Entropy is 0 at T = 0 Kelvin
0th Law of Entropy
if Ta = Tb, and Ta = Tc,
therefore, Tb = Tc
What is the Input and Output of a Heat Engine?
Input: Qhot
Output: Work(out)
Formula for Output Work in a Heat Engine
Wout = Qh - Qc
Formula for Heat Engine Efficiency(e)
Derivation:
e = Output / Input
e = Wout / Qh
e = (Qh - Qc) / Qh
Final Ans: e = 1 - (Qc / Qh)
Formula for Heat Engine CARNOT EFFICIENCY
e = 1 - (Tc / Th)
IN KELVIN
Formula for Refrigerator CARNOT Coefficient of Performance
COP = (Th - Tc) / Tc
IN KELVIN
What is the Input and Output of a Refrigerator?
Input: Work(in)
Output: Qcold
Formula for Output Qc in a Refrigerator
Qc = Qh - Win
Formula for the Coefficient of Performance of a Refrigerator
Derivation:
COP = Output / Input
COP = Qc / Win
Final Ans: COP = Qc / (Qh - Qc)
What is the Input and Output of a Heat Pump?
Input: Work(in)
Output: Qhot
Formula for Input Work in a Heat Pump
Win = Qh - Qc
Formula for Coefficient of Performance of a Heat Pump
Derivation:
COP = Output / Input
COP = Qh / Win
Final Ans: COP = Qh / (Qh - Qc)
Another parameter that measures refrigerator performance
Energy Efficiency Ratio (EER)
Formulas for Energy Efficiency Ratio(EER)
EER = (Q per Hour)/Power EER = 3.42 . COP
Q - MUST BE IN BTU/hour
Kevin-Planck Statement
Assume a Heat Engine:
Because Qc can never become 0,
from the formula Wout = Qh - Qc,
Conclusion: Wout can never be equal to Qh
Clausius Statement
Assume a Refrigerator/Air conditioner:
Because the input work(Win) required to cool a system cannot be just 0,
from the formula Qc = Qh - Win,
Conclusion: Qc cannot equal Qh
Restatement: “Heat does not flow from cold to hot normally”
Caratheodory Statement
At equilibrium, There are equilibrium states inaccessible by an adiabatic process
Nernst Postulate
from the 3rd Law if Thermodynamics (Tk = 0 Kelvin, The entropy is zero), “It is impossible to achieve this state with finite number of operations”
The amount of Disorder in a system
entropy
The formula for the Change in Entropy
ΔS = Q / T
Q - Heat
T -Temperature
When Solid transfoms Into Liquid and/or Liquid into Gas(S»»L»»G), Change in Entropy (Increases/Decreases)
Increases
When Gas transfoms Into Liquid and/or Liquid into Solid(G»»L»»S), Change in Entropy (Increases/Decreases)
Decreases
What are the processes involved in a Carnot Cycle
Involves 2 Adiabatic and 2 Isothermal Processes to complete one cycle (4 processes in total)
The Phase transformation from Gas to Solid
Deposition
The Triple Point of Water is Found at what temperature?
0.01 Celcius
Water is most dense at what temperature?
4 Celcius
How much of a Proton’s Energy is attributed to Heat?
1/3 of Proton’s energy is equal to heat
Unit of electron volts (eV)
Joules per Coloumb (J/C)
If in problems a gas is not specified if whether monoatomic or diatomic, what do we assume by default?
the gas is monoatomic
Kinetic Energy of MONOATOMIC gas
KE = 3.K.T / 2
k - boltzmann constant
T - Temp. in Kelvin
Kinetic Energy of DIATOMIC gas
KE = 5.K.T / 2
k - boltzmann constant
T - Temp. in Kelvin
Vrms of MONOATOMIC gas (given Temperature and mass)
Vrms = sqrt( (3KT / m)
k - boltzmann constant
T - Temp. in Kelvin
m - mass in kg
Vrms of DIATOMIC gas (given Temperature and mass)
Vrms = sqrt( (5KT / m)
k - boltzmann constant
T - Temp. in Kelvin
m - mass in kg
Vrms of MONOATOMIC gas (given Temperature and Molar mass)
Vrms = sqrt( (3RT / MM)
R - 8.314 J/K.mol
T - Temp. in Kelvin
MM - Molar Mass
Vrms of DIATOMIC gas (given Temperature and Molar mass)
Vrms = sqrt( (5RT / MM)
R - 8.314 J/K.mol
T - Temp. in Kelvin
MM - Molar Mass
