Thermodynamics and Electrochemistry Formulas

Spontaneous

Describes a process that can happen without external energy

Entropy

S = (q/T)

Temp in Kelvin; q = (J of heat)

ΔS

S final - S initial

What are the three types of molecular motion

Translational: Point A → B

Vibrational: Motion between atom bonds

Rotational: Turning of molecules around an axis or own sigma bonds

Entropy Formula dependent on microstates

S = K * lnW

Boltzmann Constant(K)

1.38 × 10^-23 J/k

W(microstates)

W = (N!)/(a!b!c!…)

N = total # of molecules

a, b, c = total molecules within energy layer

ΔG rxn

∑ΔG products - ∑ΔG reactants

Gibbs Free Energy Equation

ΔG = ΔHsys -TΔS sys

When ΔG is postive?

The reaction is non spontaneous

When ΔG is negative

The reaction is spontaneous

ΔG dependant on equilibrium constant (standard conditions)

ΔG = -RT * lnK

R = 8.314 J/mol k

ΔG non standard conditions

ΔG = ΔG initial + RT *lnQ

Q =

(products)^x / (reactants)^y

Volt

J/C

E cell

E reduction(cathode) + Eoxi(anode)

Eoxi

-(Ered)

ΔG Cell Behavior(standard conditions)

ΔG = -nFE

n = moles of electron transfered

F = Feymanns Constant

E = Cell Potiental

Nernst Equation (non-standard cell condition)

E = Ecell - (0.0592)/(n) * logQ