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24 Cards in this Set
- Front
- Back
1st Law of Thermodynamics
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The total energy of the universe is constant, that is, it cannot be created or destroyed. (You can't win.)
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2nd Law of Thermodynamics
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Processes tend to run toward entropy. (You can't break even).
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Equation for internal energy of a system
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dE= q+w, where dE is proportional to Temp
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Isochloric system
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A system where thre is no change in volume.
dE=q because w=-PdV=0 |
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Work of a system
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w=-pdV
when a piston moves up, there is a gain in PE, system is doing work on the surroundings |
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Isobaric SYstem
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dP=0
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Isothermal System
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dT=0
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Adiabatic System
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no heat is transferred between the system and its surroundings
all energy is transferred as work |
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Entropy
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the measurement of things moving toward disorder
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Enthalpy
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the energy that must be put into a bond in order to break it
when a bond is formed, energy is released |
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Heat of a rxn
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change in enthalpy (dH)
-dH= exothermic +dH= endothermic |
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Heat of a rxn for diatomic and monatomic elements in their natural state
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dH=0
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Standard state
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298K (25C), 1 atm pressure, 1M
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Hess's Law
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The sum of energies absorbed or released in all steps will be the same as that of the overall reaction.
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Rules for Applying Hess's Law
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1. If a rxn is reversed, the sign of dH is reversed
2. If an equation is multiplied by a constant, dH is also multiplied by the same constant |
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Gibbs Free Energy
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dG= dH-TdS
-dG= spontaneous rxn +dG= nonspontaneous rxn dg=0= equilibrium |
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Spon or Nonspon?
-dH +dS |
spon (-dG)
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Spon or Nonspon?
+dH +dS |
spon at high temps (-dG)
nonspon at low temps (+dG) |
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Spon or Nonspon?
-dH -dG |
nonspon at high temps (+dG)
spon at low temps (-dG) |
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Spon or Nonspon?
+dH -dS |
Nonspon (+dG)
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t/f
Catalysts are able to change dS, dH, and dG |
F
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Thermodynamics and Equilibrium
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dG (standard state)= -2.3 RTlog Keq, where Keq=10^(-dG/5700)@STP
-dG (standard state)= spon, Keq> 1 +dG (standard state) = nonspon, Keq<1 0=dG (standard state)= equil, Keq=1 |
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Mass defect
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the difference in the masses of individual nucleons and their mass when combined
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what is the equation to find the energy that is made when nucleons come together
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E-mc^2
c= speed of light m = mass defect |