Physical Chem Flashcards
write the equation for internal energy
U=w+q
Kinetic energy equation
Ekin=0.5mv2
difference between a closed and isolated system
closed system allows energy to pass through
write the equation for enthalpy using internal energy
H=U+pv
write the equation for the change in enthalpy at a constant pressure and what is the measurable change in the equation
^H=^U+p^q=^w+^q+p^q
if the only work is change in volume, what does w=
w=-p^v
assuming that the only work done is change in volume (constant pressure), rewrite this into a measurable change
^H=^U+p^v=^q+^w+p^v
^H=^U+p^v=^q-p^v+p^v
^H=^q-p^v+p^v=^q
^H=^q
state the law of entropy in an isolated system
can only increase
what is entropy proportional to
heat transferred from the system to its surroundings
write the equation for entropy at equilibrium and what can be substituted
^S=^q/T
^S=^H/T
in ^S=^H/T
what happens to S and H in exo/endothermic reactions
exothermic - they both decrease (<0)
endothermic - they both increase (>0)
write the equation for total entropy and what value does it have to have for a spontaneous reaction
^S total=^S surroundings +^S system
total entropy must be positive
definition of Gibb’s Free Energy
the energy from a reaction that is free to do work
write the equation for Gibb’s Free Energy
^G=^H+T^S
name the macrostates
pressure
volume
temperature
