Lecture 1 Flashcards
only gases have different
cp and cv values as solids and liquids are incompressible so cp and cv are the same
extensive vs intensive
intensive means independent of mass
open system
can exchange mass and energy
closed system
can exchange energy with surroundings but not mass
isolated system
cannot exchange mass or energy
Cp
heat capacity at constant pressure (doesnt actually vary much with pressure)
Cv
heat capacity at constant volume doesnt vary much with volume
change in enthalpy =
Cp*changein temperature
change in internal energy
Cv * change in temperature
closed system important variable
internal energy
to calculate use Cv for U
dont worry about change in volume
open system important variable
enthalpy
calculate use Cp for H
dont worry about change in pressure
zeroth law of thermodynamics
If A is in thermal equilibrium with B and B is in thermal equilibrium with C then A and C are in thermal equilibrium.
all same temp no temp flows between them
adiabatic process
Adiabatic means no heat flows into or out of the system.
adiabatic practical examples
situation occurs so fast that heat cannot escape fast enough to make a difference ie piston cylinder
adiabatic options
perfectly insulated system (never happens)
boundary at same temp as the system
internal energy
total energy of an ideal gas molecule
equation of state
pV = nRuT
portion of internal energy associated with kinetic energy of the molecules called
sensible energy
heat is
form of energy that is transferred between two systems (or a system and its surroundings) by virtue of a temperature difference.
work is
Work is the energy transfer associated with a force acting through a distance
work is path dependent
see powerpoint
heat flowing from the surroundings into the system is taken as
positive
work done by the system on the surroundings is taken as
positive
change in energy
heat in - work out