12A.2 Flashcards
the total entropy change of a process consists of two components what are they?
- the entropy change of the soundings
- the entropy change of the system
the total entropy change is defined as?
change in S total = change in S system + change in S surroundings
for a reaction to be spontaneous the total Entropy needs to be
positive
How is the change in entropy of the system calculated
sum of S of products - sum of S of reactants
what are the standard conditions
100KPa 298K
How is the change in entropy of the surroundings calculated
—- change solution enthalpy / T (temp)
for endothermic reaction the S system will always be
Negative
for exothermic reaction the S surroundings will always be
positive
why does diamond have less entropy than graphite
because diamond is arranged in 3 dimensions lattice where as graphite is arranged in 2 dimension lattice allowing more freedom for the particles to move between the layers so more arrangements more entropy
when using the equation S(surroundings) = - change in solution enthalpy / T what should you there
either convert H into J for S into KJ since they don’t have the same measurements
what is thermodynamically not stable reaction
a reaction that cant take place in standard condition (non spontaneous)
what is a kinetically stable reaction
a reaction with such high Ea that it wont take place spontaneously at room temperature
when increasing the heat of a cold molecules compared to a hot one what will happen to entropy
in both cases entropy increases, but more for the cold molecules since the hot molecules particles are already moving around vigorously
how do we know if water will freeze by its S total
if its a negative value it wont freeze
when freezing water and the change isn’t thermodynamically spontaneous the water….
will not freeze on its own
