Week 1 Introduction and First Law of Thermodynamics Flashcards
what typically happens when a system is left to itself
macroscopic system reaches a steady state described by P, V, T
what are the 3 thermodynamic variables and what is true of them at thermo eqm
P - Pressure
V - Volume
T = Temperature
Don’t have to be related at thermo eqm
what are the two types of thermo variables and define them
Extensive - They are additive and proportional to amount of substance
Intensive - Not additive and are normalised (not dependent on amount of substance)
what is the 0th Law of Thermodynamics
If two bodies are in thermo eqm with a third body at the same temp then they will be in eqm with each other
what does the 1st Law of Thermodynamics do
Govern transfer of internal energy
give the three properties of internal energy
It is an extensive property
sum of all forms of energy in a system
is a function of state
what is the 1st Law equation
change in energy = heat added + work done on system
E= Q + W
why is E a function of state and Q and W are not
E is a function of other thermodynamic variables whereas Q&W depend on the process so aren’t a function of state.
what is true of the magnitude of the change in property of a system
independent of path
dependent on initial and final states
what is the infinitesimal first law equation
dE = dW + dQ
define a cyclic process
process that begins and ends at the same eqm state with Ef = Ei
define a quasi-static process
one that proceeds slowly enough that the system passes through a sequence of eqm states
what are the three conditions for a process to be reversible
> No stick/slip friction
Process must be quasi-static
Process shouldn’t cause permanent change to the system
