TP1 Flashcards
What is absolute 0?
The temperature at which an ideal gas would have 0 pressure (-273°C)
What is the relationship between two different temperatures and pressures?
T2/T1 = p2/p1
What is the relationship involving the triple point of water?
T = T(trip) p/p(trip) = (273.16K) p/p(trip)
How do we convert between temperature scales?
Tf = 9/5 Tc + 32
Tc = 5/9 (Tf - 32)
Tk = Tc + 273.15
What is the relationship for length expansion?
Ľ = ą l0 DT
(l = l0 + Ľ)
What is the relationship for volume expansion?
DV = BV0 DT
(B = 3ą)
How do thermal stresses occur?
When expansion or contraction is prevented by clamping
What is the relationship for thermal stress?
(Ľ/l0) = ą DT
What is Youngs Modulus?
Y = (F/A) / (Ľ/l0)
(How easy an object is to stretch or compress)
How do we balance thermal stress?
F/A = -ąY DT
What are the types of deformation?
Plastic (permanent)
Elastic (reversible)
What are the yield point and the fracture point?
Yield point = where deformation goes from elastic to plastic
Fracture point = where there is too much deformation and the object breaks
What is the first law of thermodynamics?
Total energy is conserved
(DU = Q - W)
What is the relationship for specific heat capacity?
Q = cm DT
What is the relationship for molar mass?
m = nM
What is the relationship for molar heat capacity?
Q = cm DT
= cnM DT
= Cn DT
(C = cM)
What is the Dulong-Petit law?
C = 3R ≈ 24.9 J.mol^-1.K^-1
(R = molar gas constant)
What is latent heat?
Heat that is absorbed or emitted during a phase change
What is the relationship for latent heat?
Q = +/- mL
What is calorimetry?
The measurement of heat
What is the calculus relationship for heat current?
H = dQ/dt
What is conduction and what is it dependent on?
Transfer of energy between atoms, dependent on thermal conductivity
What are the relationships for heat current in conduction?
H = -k (A DT)/l
H = -kA dT/dx
(k= constant of thermal conductivity)
What does thermal resistance indicate?
Insulation properties
What are the relationships for thermal resistance?
H = -A DT/R(t)
R(t) = l/k
What is convection and what is it dependent on?
The transfer of heat by motion of fluid from one region to another, dependent on fluid flow
What is the heat current relationship for convection?
H = -hA DT
(Free laminar flow: hą|DT|^1/4)
(Turbulent flow: hą|DT|^1/3)
What is radiation and what is it dependent on?
The transfer of heat by em waves, dependent on emissivity
What is the heat current relationship for radiation?
H = -AeóT^4
What is a black body?
A perfect radiator and absorber, emissivity 1
What is an ideal reflector?
A perfect reflector, no radiation/absorbtion, emissivity 0
What is Wien’s displacement law?
ŷm ą 1/T = bw/T
(ą = 2.9x10^-3mK)
What is the ideal gas equation?
pV = nRT = m/M RT
(R = 8.314J.mol^-1K^-1)
What are states of gas defined by?
State variables: mass/n of moles, volume, pressure, temperature, all related by equations of state
What is Van der Waals equation?
(p + a n^2/v^2)(V-bn) = nRT
(a — attractive force)
(b — finite size)
What is the relationship between force and potential?
F = -dU/dr
What are isotherms?
Lines of constant temperature on a graph
Plotting Van der Waals equation shows phase changes
P can cause phase change as well as T
