Revision Lecture Flashcards
Three approaches to describing properties of matter:
Microscopic, macroscopic and statistical
Macroscopic approach to describing properties of matter (SPVIE)
S: State variables describe properties of matter
P: Properties measured at macroscopic scale e.g. P,V,T
V: Variables are related to equations of state
I: Ideal gas equation PV=muRT
E: Excludes microscopic knowledge (no need for atomic behaviour).
Microscopic approach to describing properties of matter (TMCIC)
T: Trajectory and momentum of each atom followed
M: Momentum includes collisions with surroundings
C: Computational effort is immense
I: Impossible to apply due to large number of atoms
C: Count of atoms is roughly Avogadro’s number (6x10^23)
Statistical approach to describing properties of matter (STAMP)
S: Statistical properties of microscopic behaviour
T: Translates into macroscopic variables
A: Atomic or molecular behaviour as basis
M: Macroscopic state variables derived from statistics
P: Properties linked to equations of state
Draw a graph for a non-equilibrium process
Draw a graph for a quasistatic process
Give examples of an irreversible process
Anything involving friction-bursting a balloon, melting ice in warm water etc
Draw a graph for a reversible process
Label the diagram
What is an equation of state?
A constitutive equation describing the macroscopic state of matter in equilibrium
Equation of state…mathematical relation between
Mathematical relation between two or more state functions associated with matter i.e. P,V,T or internal energy.
Give two examples of an equation of state?
Ideal gas law, Van der waal’s equation for a real gas
The pressure in ideal gas law has…
A functional dependence P(mu,T,V)
Equations of state do not give information about…
how the gas got to this particular state, just the relationship between the state functions.
What does this mean?
The total energy content of a system U, is the sum of the net heat energy that has entered the system Q and the net work done on the system W.
WD on a gas in a reversible process…
is a negative integral
What does this mean?
Efficiency is proportional to the temperature difference
n<1 due to Kelvin’s statement of the second law
