Exam 2 Flashcards
Celcius to Fahrenheit Formula
Tf = (9/5)*Tc+32
Fahrenheit to Celcius Formula
Tc = (5/9)*(Tf-32)
Celcius to Kelvin Formula
Tk = Tc + 273.15
Ratio between two units of temperature
(T-Tf)/(Tb-Tf) where
T is temperature
Tf is freezing point of water
Tb is boiling point of water
Triple Point
The point in which all three phases exist at a certain temperature and pressure.
Linear Thermal Expansion Formula
ΔL = αLoΔT where
α is the coefficient of linear expansion
Lo is the original linear dimension
Symbol for Heat
Q
Equations for Heat
Q = mcΔT Q = nCΔT
What is the difference between c and C?
c is the specific heat of a substance.
C is the molar heat capacity of a substance.
When is Q positive or negative?
Q is positive when heat is added to a body.
Q is negative when heat is removed from a body.
Equation for Heat during a Phase Change
Q = ±mL where
L is the heat of fusion, vaporization, or sublimation of an object.
Formula for Heat Current (Conduction)
H = kA((Th-Tc)/L) where
k is the thermal conductivity of the material
A is the area through which the heat flows
Th is the hot temperature
Tc is the cold temperature
L is the length of the heat-flow path
What is the relationship between Heat and Heat Current?
H = dQ/dt
What are the three types of heat transfer?
Conduction
Convection
Radiation
Formula for Radiation heat transfer
R = L/k where
k is the thermal conductivity of the material
L is the length of the heat-flow path
Ideal-gas Equation
PV=nRT where
R is a constant
What is the value of the constant R?
8.314 J / mol. K
Formula for Translational Kinetic Energy of a Gas as a Whole
Ktr = (3/2)*nRT
Formula for Translational Kinetic Energy of a Molecule
(1/2)mv^2 = (3/2)kT where
k is the Boltzmann constant
What is the value of the Boltzmann constant?
1.380*10^23
What is the molar heat capacity for a monatomic gas?
Cv = (3/2)*R
What is the molar heat capacity for a diatomic gas?
Cv = (5/2)*R
What is the molar heat capacity for a monatomic solid?
Cv = 3R
Formula for Work in a Thermodynamic Process
W = PΔV W = ∫P dV from V1 to V2
What is the symbol for change in internal energy?
ΔU
Zeroth Law of Thermodynamics
If object A is in thermal equilibrium with object B, and object B is in thermal equilibrium with object C, then object A is in thermal equilibrium with object C.
First Law of Thermodynamics
The total energy in a closed system is constant
Formula for First Law of Thermodynamics
ΔU = Q - W where
ΔU is change in internal energy
Q is heat
W is work
What are the kinds of thermodynamic processes?
Adiabatic
Isochoric
Isobaric
Isothermal
What is an adiabatic process?
A process where there is no heat transfer but pressure and volume change.
What is an isochoric process?
A process in which volume is constant but pressure changes.
What is an isobaric process?
A process in which pressure is constant but volume changes.
What is an isothermal process?
A process in which temperature remains constant.
What is the difference between Cp and Cv?
Cp is the specific heat capacity of a substance at constant pressure.
Cv is the specific heat capacity of a substance at constant volume.
The is the relationship between Cp and Cv?
Cp = Cv + R
What is the ratio of heat capacities?
γ = Cp/Cv
What is are the formulas for work in an ideal process?
W = nCvΔT W = (Cv/R)*Δ(PV) W = (1/γ-1)*Δ(PV)
What is the difference between a reversible and irreversible process?
A reversible process is one whose direction can be reversed by a minimal change in the conditions of the process.
All other thermodynamic processes are irreversible.
What is the formula for the equipartition theorem?
U=(1/2)fNkt where
f is 3 for monatomic processes and 5 for diatomic processes
Formula for Work done by a Heat Engine
W = |Qh|-|Qc|
Formula for efficiency of a Heat Engine
η = W/Qh = 1-|Qc/Qh|
Formula for efficiency of an Otto Cycle
η = 1-(1/r^(γ-1)) where
r is the compression ratio
γ is the ratio of heat capacities
What is the Second Law of Thermodynamics?
Total entropy in an isolated system can never decline.
Formula for Efficiency of the Carnot Cycle
η = 1-(Tc/Th) = (Th-Tc)/Th
What is Entropy?
Entropy is the quantitative measure of randomness or disorder of a system.
Formula for Entropy
ΔS = ∫ dQ/T = Q/T where
Q is heat
T is absolute temperature
Formula for Compression Ratio
r = Vmax/Vmin