thermodynamically unfavorable
cathode
reduction happens, gaining electrons
oxidation happens, losing electrons
cell potential, Ecell, electromotive force (emf)
1 joule of work / coulomb of charge transferred
J/C = units
galvanic cell
chemical energy is converted to electrical energy with spontaneous redox reaction
Voltage
consists of oxidizing agent in one compartment that pulls electrons through a wire from a reducing agent
how K and G relate to each other
exergonic reaction
products have less energy than reactants, spontaneous, graph will end lower than it started
what is Gibb's free energy
the energy of a system related to changes in enthalpy and entropy, at a constant temperature.
basically implies that the system is at 1 atm and using 1 M solutions.
G, S, H
S = entropy
G = Gibbs free energy
H = heat energy
2nd law of thermodynamics
entropy of an isolated system is never decreasing, only if it is in a 2 or more system
spontaneous at all Temps, delta G <0
overall cell reaction
y + z --> Y+ + Z- (G<0)
Cell potential equation
2nd law with entropy
as matter disperses, entropy increase, so, going from solid to liquid to gas would increase entropy, whilst going from gas to liquid to solid would decrease it
delta S =
charging = non-spontaneous
using = spontaneous
it has k>1, relatively low activation energy
how a reaction that is thermodynamically unfavorable occur
how do you calculate Gibbs free energy
if a reaction is thermodynamically favorable
delta G and the energy of the product is lower than that of the reactants
1. G = negative = k>1; G = positive = k
volumes proportionality with entropy
as V goes up, so does S
as the more temperature, the more energy, the mor entropy
voltage equation
V = IR
voltage = current (amps) * resistance (ohms)
is H > 0 and S > 0
3rd law of thermodynamics
as temperature goes to zero, entropy approaches a constant value
entropy
degrees of freedom of a molecule
x --> X+ + e-
1st law of thermodynamics
in an isolated system energy can neither be created or destroyed; only transferred or converted, meaning E lost = negative E gained
T=100k
spontaneous, low temperature, T delta S is small
galvanic cell vs electrolytic cell
