State of System, 0th Law, Equation of State

Question 1

Give the four laws in Thermodynamics.

Answer 1

0th Law: defines temperature (T)
1st Law: defines energy (U)
2nd Law: defines entropy (S)
3rd Law: gives numerical value to entropy

Question 2

True or false: The four laws of thermodynamics are universally valid and can be circumvented.

Answer 2

False, the four laws of thermodynamics are universally valid and cannot be circumvented.

Question 3

Give the definition of a system.

Answer 3

The part of the universe that we chose to study.

Question 4

Give the definition of surroundings.

Answer 4

The rest of the universe that we do not chose to study.

Question 5

Give the definition of a boundary.

Answer 5

The surface dividing the System from the Surroundings.

Question 6

True or false: systems can be open, closed and isolated.

Answer 6

True.

Question 7

Give the definition of an open system.

Answer 7

Mass and energy can transfer between the System and the Surroundings.

Question 8

Give the definition of a closed system.

Answer 8

Energy can transfer between the System and the Surroundings, but not the mass.

Question 9

Give the definition of an isolated system.

Answer 9

Neither mass nor energy can transfer between the System and the Surroundings.

Question 10

What are the two classes of Properties?

Answer 10

Extensive property depends on the size of the system. Intensive property is independent of the size of the system.

Question 11

What are some variables that represent extensive properties?

Answer 11

n,m,V,…

Question 12

What are some variables that represent Intensive properties?

Answer 12

T,p,V/n,…

Question 13

What are state variables?

Answer 13

Independent of the history of the system.

Question 14

What is the notation for a system at equilibrium?

Answer 14

Number of moles, element, (state of matter, p, T)

Question 15

What is the notation for a change of state in transformations?

Answer 15

Initial state = Final state
# of moles, element, (state of matter, p, T) = # of moles, element, (state of matter, p, T)

Question 16

What is the path for a transformations in change of state?

Answer 16

The arrow on the graph goes from initial to final state.

Question 17

List the different types of processes in a change of state.

Answer 17

Reversible, Irreversible, Adiabatic, Isobaric, Isothermal, Constant Volume

Question 18

Describe the process of thermal equilibrium between a hot and cold object.

Answer 18

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”.

Question 19

If A & B are thermal equilibrium, B & C are thermal equilibrium, then A & C are thermal equilibrium describes which law?

Answer 19

Zero’th Law of Thermodynamics

Question 20

What all does operational temperature need?

Answer 20

1. Substance
2. Property that depends on t
3. Reference points
4. Interpolation scheme between ref. pts

Question 21

What do the Boyle’s Law and Kevin scale apply to?

Answer 21

Ideal gases

Question 22

What is the equation for the Boyle’s Law and Kevin scale?

Answer 22

lim p->0(pV)T = [lim p -> 0(pV)tp/273.16]T define RT

Valid for all gases for p-> 0

Question 23

An ideal gas obeys ________

Answer 23

The expression pV = RT at all pressures (-> the gas molecules do not interact)

Question 24

What is the equation of the Ideal gas law?

Answer 24

pV = RT
pV = nRT

Question 25

Give the partial pressure of ith gas equation.

Answer 25

pi = niRT/V

Question 26

Give the mole fraction of ith gas equation.

Answer 26

xi = ni/n

Question 27

What is the equation of Dalton’s law?

Answer 27

pi = ni/n *p = xip

Question 28

Describe real gases and give the three versions.

Answer 28

Real gases do not necessarily obey ideal gas law.

1. Compressibility factor
2. Virial Expansion
3. van der Waals Equation of state

Question 29

Describe Compressibility factor.

Answer 29

Equation: pV = ZRT
High temp -> repulsions dominate (Z > 1) (Vreal > Videal)
Low temp -> attractions dominate (Z < 1) (Vreal < Videal)

Question 30

Describe Virial Expansion.

Answer 30

Equation: pV/RT = Z(T) = 1 + B(T)/V + C(T)/V^2 +…
As p-> 0, V->infinity -> ideal gas
B=0 -> ideal gas

Question 31

Describe van der Waals Equation of state.

Answer 31

Only two parameters, derived from molecular concepts.

Equation: (p + a/V^2)(V - b) = RT