State of System, 0th Law, Equation of State Flashcards
Give the four laws in Thermodynamics.
0th Law: defines temperature (T)
1st Law: defines energy (U)
2nd Law: defines entropy (S)
3rd Law: gives numerical value to entropy
True or false: The four laws of thermodynamics are universally valid and can be circumvented.
False, the four laws of thermodynamics are universally valid and cannot be circumvented.
Give the definition of a system.
The part of the universe that we chose to study.
Give the definition of surroundings.
The rest of the universe that we do not chose to study.
Give the definition of a boundary.
The surface dividing the System from the Surroundings.
True or false: systems can be open, closed and isolated.
True.
Give the definition of an open system.
Mass and energy can transfer between the System and the Surroundings.
Give the definition of a closed system.
Energy can transfer between the System and the Surroundings, but not the mass.
Give the definition of an isolated system.
Neither mass nor energy can transfer between the System and the Surroundings.
What are the two classes of Properties?
Extensive property depends on the size of the system. Intensive property is independent of the size of the system.
What are some variables that represent extensive properties?
n,m,V,…
What are some variables that represent Intensive properties?
T,p,V/n,…
What are state variables?
Independent of the history of the system.
What is the notation for a system at equilibrium?
Number of moles, element, (state of matter, p, T)
What is the notation for a change of state in transformations?
Initial state = Final state # of moles, element, (state of matter, p, T) = # of moles, element, (state of matter, p, T)
What is the path for a transformations in change of state?
The arrow on the graph goes from initial to final state.
List the different types of processes in a change of state.
Reversible, Irreversible, Adiabatic, Isobaric, Isothermal, Constant Volume
Describe the process of thermal equilibrium between a hot and cold object.
When a hot object is placed in thermal contact with a cold object,
heat flows from the warmer to the cooler object. This continues
until they are in thermal equilibrium (the heat flow stops). At this
point, both bodies are said to have the same “temperature”.
If A & B are thermal equilibrium, B & C are thermal equilibrium, then A & C are thermal equilibrium describes which law?
Zero’th Law of Thermodynamics
What all does operational temperature need?
- Substance
- Property that depends on t
- Reference points
- Interpolation scheme between ref. pts
What do the Boyle’s Law and Kevin scale apply to?
Ideal gases
What is the equation for the Boyle’s Law and Kevin scale?
lim p->0(pV)T = [lim p -> 0(pV)tp/273.16]T define RT
Valid for all gases for p-> 0
An ideal gas obeys ________
The expression pV = RT at all pressures (-> the gas molecules do not interact)
What is the equation of the Ideal gas law?
pV = RT pV = nRT
Give the partial pressure of ith gas equation.
pi = niRT/V
Give the mole fraction of ith gas equation.
xi = ni/n
What is the equation of Dalton’s law?
pi = ni/n *p = xip
Describe real gases and give the three versions.
Real gases do not necessarily obey ideal gas law.
- Compressibility factor
- Virial Expansion
- van der Waals Equation of state
Describe Compressibility factor.
Equation: pV = ZRT
High temp -> repulsions dominate (Z > 1) (Vreal > Videal)
Low temp -> attractions dominate (Z < 1) (Vreal < Videal)
Describe Virial Expansion.
Equation: pV/RT = Z(T) = 1 + B(T)/V + C(T)/V^2 +…
As p-> 0, V->infinity -> ideal gas
B=0 -> ideal gas
Describe van der Waals Equation of state.
Only two parameters, derived from molecular concepts.
Equation: (p + a/V^2)(V - b) = RT
