Geochem 2 : thermo

Question 1

What are the thermodynamic functions?

Answer 1

V (volume), S (entropy), U (internal energy), H (enthalpy), G (gibbs free energy), u (chemical potential)

Question 2

What are the Equilibrium Conditions for a closed system w constant T/P?

Answer 2

G is minimized, or delta G = 0, or u of every component is the same in each phase.

Question 3

How to calculate equilibrium state of multiple phases?

Answer 3

delta G = sum(n,u) 1 - sum (n,u)2

Question 4

Delta G equation

Answer 4

Delta G = -RTln(k)

Question 5

What is Q

Answer 5

Concentration quotient

Question 6

How does Q work

Answer 6

Substitute for K if not at equilibrium

Question 7

What should delta G = at equilibrium

Answer 7

0

Question 8

Ln K equation

Answer 8

LnK = (delta S)/R - ((delta H)/R)(1/T)

Question 9

How to find chemical potential with fugacity?

Answer 9

u = u0 + RTln(f/f0)

Question 10

How to find activity

Answer 10

a = number of moles * K

Question 11

What does the Claperon slope have to do with the mantle?

Answer 11

As a slab subducts, it will hit the 670 km discontinuity where ringwoodite -> perovskite. A subducted slab that’s cooler than the mantle will need to phase transition to continue sinking, but the P is not high enough. Thus it’s trapped!

Question 12

What needs to be considered for accurate calculations?

Answer 12

Variation of V and S

Question 13

how to find dG? (#2)

Answer 13

dG = VdP - SdT

Question 14

What’s the claperon equation?

Answer 14

dP/dT = deltaS/deltaG

Question 15

How to find G for a mixture?

Answer 15

Delta G = xDeltaG 1 + x DeltaG2 + deltaG mixture

Question 16

What is chemical potential for?

Answer 16

Delta G in mixtures

Question 17

What is the phase rule?

Answer 17

F = C (components) + 2 - (number of phases)

Question 18

Equation for U

Answer 18

dU = dQ - dW

Question 19

Olivine equations

Answer 19

Fayalite (Fe2SiO4) and Forsterite (Mg2SiO4)

Question 20

Pyroxene equations

Answer 20

Mg2Si2O6 and Fe2SiO6