Thermochem/Thermodynamics Flashcards
1st law of thermodynamics
Energy cannot be created nor destroyed
2nd law of thermodynamics
For a spontaneous rxn, the entropy of the universe will INCREASE
3rd law of thermodynamics
Entropy of a perfect crystal at a temperature of 0 Kelvin
Entropy has ___ and ____
system and surroundings
Entropy has ___ and ____. It is represented by what letter?
system and surroundings
Represented by Δ S
For a spontaneous rxn, what can ΔS never be?
Negative, the system and surroundings MUST add up to be positive for spon. rxn
ΔE represents what
Change in internal energy
State function
a property whose value does not depend on the path taken to reach that specific value
What are the 2 things that are NOT state functions?
q (heat), w (work) and heat capacity
If the system gains energy, q and w are
q and w are POSITIVE
If the system loses energy, q and w are
q and w are NEGATIVE
If heat is transferred from the system to the surroundings, q is
Q is NEGATIVE
If the system does work on the surroundings, w is
NEGATIVE
work equation
what is ALWAYS positive?
-PΔV
P is always POSITIVE
when ΔV is positive, w is what
NEGATIVE because our gas is losing energy
What is q?
It represents heat transfer
If heat is transferred from the surroundings to the system, q is what
POSITIVE
How do u convert C to K?
C plus 273
If you are NOT going through a phase change what equation do you use?
q=mcΔT
If you ARE going through a phase change what equation do you use?
ΔH of whatever phase change it is
ex. ΔHfusion
Are phase changes the straight lines?
Yes
If K>1, what is favored?
If K<1, what is favored?
If K=1, what does this mean?
Products!
Reactants!
P and R are equally favored
