3 - Thermodynamics Flashcards
System=
Surroundings=
Open ? ?
Closed ? ?
Isolated ? ?
Energy Mass
System= is the macroscopic body under study.
Surroundings= is everything else.
Open Yes Yes
Closed Yes No
Isolated No No
Energy Mass
State Functions=
***______ properties change with amount, and _____ properties do not.***
Heat=
Work=
W =
***if ______ is constant no work is done at all.***
State Functions= describe the state of a system.
***Extensive properties change with amount, and intensive properties do not.***
Heat= the natural transfer of energy from a warmer body to a cooler body.
Work= any energy transfer that is not heat, is work.
W = P(delta)V ((constant pressure))
***if volume is constant no work is done at all.***
Heat:
Conduction=
Convection=
Radiation=
Heat:
Conduction= is thermal energy transfer via molecular collisions.
Convection= is thermal energy transfer via fluid movements.
Radiation= is thermal energy transfer via electromagnetic waves.
1st law of thermodynamics=
(delta)E =
2nd law of thermodynamics=
1st law of thermodynamics= states that energy of the system and surroundings are always conserved.
_ (delta)E = q + w_
2nd law of thermodynamics= heat cannot be changed completely into work in a cyclical process.
K.E. avg =
Enthalpy=
(delta)H =
(delta) H =
(delta) H rxn =
K.E. avg = 3/2kT
Enthalpy= is a man-made property that accounts for this extra capacity to do PV work.
(delta)H = (delta)U + P(delta)V
(delta) H = q
(delta) H rxn = (delta)Hf products - (delta)Hf reactants
Exothermic=
Endothermic=
***_____, and not energy, dictates the direction of a reaction.***
***Reactions at equilibrium have achieved maximum ______.***
***_______ increases with number, volume, and temperate.***
Exothermic= (-(delta)H)
Endothermic= (+(delta)H)
***Entropy, and not energy, dictates the direction of a reaction.***
***Reactions at equilibrium have achieved maximum universal entropy.***
***Entropy increases with number, volume, and temperate.***
(delta) G =
- (delta)G indicated a _______ reaction!!!
(delta)G = (delta)H -T(delta)S
(delta)G (delta)H (delta)S
? ? ?
? ? ?
? ? ?
? ? ?
(delta) G = (delta)H - T(delta)S
- (delta)G indicated a SPONETANEOUS reaction!!!
(delta)G = (delta)H -T(delta)S
(delta)G (delta)H (delta)S
+ + -
- - +
+/- - -
+/- + +
Zeroth law=
Third law=
Zeroth law= two bodies in thermal equilibrium with the same system are in thermal equilibrium with each other. (In other words, temperature exists and is a state function.)
Third law= a perfect crystal at zero kelvin is assigned an entropy value of zero. All other substances and all temperatures have a positive entropy value (zero kelvin is unattainable).