Thermochemistry and Phase Changes Flashcards
Gibbs free energy
deltaG=deltaH-TdeltaS
deltaG= -RT lnKeq
bond breakage
endothermic
bond formation
exothermic
entropy (S)
- measure of disorder/randomness
- increases from solid to liquid to gas
boiling point
-more polar, stronger interactions, higher bp
-hydrogen bonding, stronger int, higher bp
-higher vapor pressure, higher bp
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gas to solid
deposition
solid to gas
sublimation
liquid to solid
fusion/melting
solid to liquid
freezing
liquid to gas
vaporization
gas to liquid
condensation
first law of thermodynamics
- change in internal energy of a system is the sum of the change in heat and the work for that system
- deltaU = Q - W
second law of thermodynamics
all spontaneous processes in an isolated system lead to an increase in entropy
isothermal process
- when pressure of a gas increases, the volume decrease and visa versa
- U=0 is gas is ideal (W=Q)
isobaric process
- when the volume of a system increases its temperature will increase as well
- W = PdeltaV
isovolumetric process
- volume remains constant
- work done = 0
- deltaU = Q
adiabatic expansion or compression
- no heat is transferred
- change in internal energy is opposite of work done by the system
- deltaU = -W
open system
can exchange energy and matter with the environment
closed system
can exchange energy but NOT matter with the environment
isolated system
CANNOT exchange energy or matter with the environment
