gen Chem page 4 Flashcards
first law of thermo
delta U= Q-W
Q is heat added
-W is work done by system
+W is work done to system
heat transfer no phase change
q=mc delta T (use C or K)
heat transfer during phase change
q=mL
L is latent heat like H vap H fusion
generalized enthalpy of reaction
delta H rxn= H products - H reactants
unit is Kj/mol
standard enthalpy of reaction
delta H rxn= sum of (delta Hf products- delta Hf reactants)
bond enthalpy
delta H rxn= delta H bonds broken- delta H bonds formed
total energy absorbed- total energy released
entropy
delta S= Q rev/T
unit J/K
second law of therm
delta S universe= delta S system + delta S surroundings >0
standard entropy of reaction
delta S rxn= sum of (delta S, f products - delta S, f reactants)
gibbs free energy
delta G=delta H- TdeltaS
+ H and + S
spontaneous at high temps
-H and -S
spontaneous at low temps
-H and + S
- G (spontaneous)
+H and -S
+G (nonspontaneous)
standard gibbs free energy of reaction
delta G rxn= sum of (delta G, f products- delta G, f reactants)
standard gibbs free energy from eq constant
delta G rx= -RT ln Keq
gibbs free energy from reaction quotient
delta G (not standard)= delta G rxn std + RT ln Q= RT ln Q/Keq
isothermal
Q=W and curve is hyperbolic (P on y axis and V on x)
adiabatic
no heat exchange
delta U=-W
also hyperbolic like isothermal
isobaric
same pressure
horizontal line
isovolumetric or isochoric
delta U= Q
vertical line
specific heat for water
1 cal/gK or 4.2 J/gK
or C instead of K
heat capacity=
mc
state functions
path independent
under Pressure and feeling Dense all I want is to watch TV and get HUGS
water has a unique P vs T phase diagram because
density of ice is less than density of water.
triple point
where all lines meet- all phases in equil
critical point
at end of gas/liq line where phase boundaries vanish and gas and liquid coexist
STP
273 K
standard temp
298 K
