Oceans - Entropy Flashcards
what is entropy?
the number of ways that energy can be distributed or arranged
what is the symbol for entropy?
S
what are the units for entropy?
J K-1 mol-1
what is entropy dependent on?
state of the molecules involved
no. energy levels
how does entropy change depending on physical state?
solids - low entropy
gas - very high entropy
why is entropy higher in gases than solids or liquids?
more ways the molecules can be distributed - therefore more ways energy can be distributed
how does the no. energy levels in a molecule affect its entropy?
more energy levels = higher entropy
if a system is disordered, what will the value of S be?
high
if a system is ordered, what will the value of S likely be?
low
what is the symbol for the entropy change of a system?
ΔSsys
how is ΔSsys calculated?
(no. of the product compound present x S of compound) + (no. product compound present x S) … - (no.reactant compound present x S) …..
what is the symbol for the total entropy change of a process?
ΔSTOTAL
how is ΔSTOTAL calculated?
ΔSTOTAL = ΔSsys + ΔSsurr
what is the symbol for the entropy change of surroundings?
ΔSsurr
how is ΔSsurr calculated?
- (ΔHr / T)
if ΔSTOTAL is positive, what does this tell us about the reaction?
it is possible
if ΔSTOTAL is negative, what does this show about the reaction?
it is impossible
if ΔSTOTAL is 0, what does this show about the reaction?
it is at dynamic equilibrium
if ΔSsys and ΔHr are positive, when will the reaction occur?
above a given temperature
if ΔHr is positive and ΔSsys is negative, when will the reaction occur?
never - reaction is impossible
if ΔHr is negative and ΔSsys is positive, when will the reaction occur?
it will always be possible, no matter the temperature
if ΔHr and ΔSsys are both negative, when will the reaction occur?
below a given temperature
