Thermodynamics

Question 1

Potential energy and kinetic energy

Answer 1

Kinetic: energy associated with motion
- can be measured
Potential: stored energy
- can not be measured directly

Question 2

Enthalpy

Answer 2

The heat absorbed or released during a process
Exothermic: energy released (delta H -)
Endothermic: energy absorbed (delta H +)
See notes

Question 3

Spontaneous and nonspontaneous process

Answer 3

First law of thermodynamics: conservation of energy
- energy can be converted between different types, but cannot be created or destroyed
Spontaneity process is based on the difference in energy between the final and initial states
- spontaneous if direction toward equilibrium and total energy goes down
- if spontaneous in one direction then nonspont the other

Question 4

Entropy

Answer 4

• a mixture of the randomness or degrees of freedom
• phase affects entropy
• number of particles affects entropy
• temperature affects entropy: increasing S increases T
  See notes for increasing and decreasing entropy

Question 5

Entropy: 2nd Law of Thermodynamics

Answer 5

• in any spontaneous process
  DeltaSuniverse=deltasystem+deltasurroundings > 0 J/K*mol

Question 6

Entropy: 3rd Law of Thermodynamics

Answer 6

• S=0 J/K*mol

Question 7

Gibbs Free Energy

Answer 7

• G=H-TS
• negDeltaG is spont and exergonic
• posDeltaG is nonspont and endergonic
• zero DeltaG = 0 and equilibrium

Question 8

Spontaneity on Gibbs

Answer 8

• spont at high T: (?)=(+)-(+)(+)
• spont at low T: (?)=(-)-(+)(-)
• spont (-)=(-)-(+)(+)
• nonspont (+)=(+)-(+)(-)

Question 9

Gibbs Free Energy definition

Answer 9

• the total free energy is theoretical
• max amt of work that can be done bye the system (spont)
• max amt of work required to be done on the system (nonspont)

Question 10

Calculating G

Answer 10

Grxn=EGproducts-EGreactants
Grxn=-RTln(K)
Standard Cell Potential= Grxn=-nFEcell
K=e^(-Grxn/RT)
- nonstandard conditions calls for balancing the rxns by reversing or multiplying and adding H2O, H+, and electrons