ChE Thermodynamics Flashcards
Which law is the basis for the manufacture of thermometer?
Zeroth Law of Thermodynamics (thermal equilibrium)
Who coined the Zeroth Law of Thermodynamics?
Ralph Howard Fowler
These properties depend on the current state of the system and not on how the system reaches that state
State functions
Other name for the first law of thermodynamics
Law of Conservation of Energy (energy can neither be created nor destroyed and can only be transformed in various forms)
Who coined the Law of Conservation of Energy?
Rudolf Julius Emmanuel Clausius
Examples of state functions
Enthalpy (H), Entropy (S), Temperature, Pressure, Internal Energy
Examples of path functions
Heat (Q) and Work (W)
Which of the following statement is correct?
A. The standard heat of formation of an element is negative.
B. Since dH = dU + dPV and can never be equal to dU
C. Q and W are state functions
D. Q + W is a state function
D.
Formula for internal energy (U)
U = Q + W
It is the energy needed to create the system
Internal Energy (U)
It is the total heat of the system
Enthalpy (H)
Formula for enthalpy
dH = dU + dPV
For constant volume (isochoric) process, heat (Q) is equal to?
Internal energy (U)
For constant pressure (isobaric) process, heat (Q) is equal to?
Enthalpy (H)
Formula for enthalpy (H) during isobaric processes
dH = integral of CpdT
Formula for internal energy (U) during isochoric processes
dU = integral of CvdT
Formula for CV at constant volume process
Cv = (partial derivative of U)/(partial derivative of T)
Equation which relates pressure, volume, and temperature of a gas is called
Equation of state
The equation, PV=nRT is best obeyed by gases at
low pressure, high temp
The compressibility factor of a gas is:
A) not a function of pressure
B) not a function of its nature
C) not a function of its temperature
D) Unity, as it followes PV=nRT
D.
For monoatomic gases, Cp/Cv is equal to?
1.67
For diatomic gases, Cp/Cv is equal to?
1.4
Cp and Cv formulas for monoatomic gases
Cp = 5R/2
Cv = 3R/2
Cp and Cv formula for diatomic gases
Cp = 7R/2
Cv = 5R/2
What happens to the internal energy of a gas during an isothermal process?
Remains unchanged
In an adiabatic process
Heat transfer is zero
From PV^n, when n=0, the process is
Isobaric
From PV^n, when n=1, the process is
Isothermal
From PV^n, when n=sigma, the process is
Adiabatic
A solid is transformed into vapor without going through the liquid phase at?
Below the triple point, or at triple point
Formula for irreversible work when reversible work is positive
Wirrev= Wrev/efficiency
Formula for irreversible work when reversible work is negative
Wirrev= Wrev(efficiency)
Other formula for virial coefficient of state
PV/RT = (1+ B/V+ C/V^2)
Adiabatic Relations Page sa perry’s
10-64
Actual work divided by the corresponding ideal work is known as ___ efficiency.
Turbine
Heat capacity is defined as C = dQ/dT, what is the difficulty about the relationship of C to Q which are supposedly state functions?
A. It is a process-dependent quantity
B. It indicates that small temp changes have smaller capacities
C. It is not an intensive property
D. It presents heat as energy in transit
A.
Which gives the most work we can get out of an adiabatic system?
Reversible expansion
What happens to delta U when work is done by the system during the adiabatic expansion of ideal gas?
Decreases
Formula for Tr and Pr
Tr = T/Tc
Pr = P/Pc
