First law of thermodynamics
Conservation of energy (energy can’t be created or destroyed)
Second law of thermodynamics
For spontaneous process, the entropy of the universe increases
Third Law of thermodynamics
A perfect crystal at 0K has zero entropy
Change in internal energy equation
Δ(E) = q + w
E -> change in internal energy
q -> heat
w –> work
Work
w = -PΔV (most common)
Gas in a piston: transfer of heat
locks piston
Expanding gases
Cool
Compressing gases
Warm
Isobaric
( ΔP = 0) constant pressure
Isochoric
(ΔV = 0) so w=0 Constant volume
Isothermal
(ΔT = 0 so ΔE = 0) Constant temperature
Adiabatic
(q=0) No heat
Expansion
Increase in volume, no work
Compression
Decrease in volume, increase work
Are heat and work state functions?
No
State Functions
independent of pathway (only cares for initial & final states)
Entropy (S): phases of matter, from low to high
s
Enthalpy (H): Exothermic & Endothermic
Exothermic: (ΔH 0) surroundings get cold
Bonded atoms have ________ energy
lower
Bonds breaking is
endothermic
Bond making is
exothermic
ΔH =
∑D(broken) - ∑D(formed)
Catabolism
Exothermic
Anabolism
Endothermic
Enthalpies of formation
ΔH°rxn = Σ ΔH°f (products) - Σ ΔH°f (reactants)
Hess’ Law: Formation Reactions:
- Forms 1 mol of product
2. All elements are in standard state
Gibb’s Free Energy (G)
ΔG = ΔH - (TΔS)
ΔG
Spontaneous K>1, favors products
ΔG>0
Non-spontaneous K
ΔG=o
At equlibrium
ΔH (-) ΔS (+)
Spontaneous at ALL temperatures
ΔH (+) ΔS (-)
Non-spontaneous at ALL temperatures
ΔH (-) ΔS (-)
Spontaneous at LOW temperatures (condensation)
ΔH (+) ΔS (+)
Spontaneous at HIGH temperatures (Boiling)