is H < 0 and S < 0
T=100k
spontaneous, low temperature, T delta S is small
cathode
reduction happens, gaining electrons
galvanic cell vs electrolytic cell
galvanic = anode is negative and cathode is positive
electrolytic = anode is positive and cathode is negative
how K and G relate to each other
is H > 0 and S > 0
T = 500k
spontaneous, high temperature, T delta S is large
non-spontaneous is...
thermodynamically unfavorable
3rd law of thermodynamics
anode
oxidation happens, losing electrons
charging a battery vs using a battery
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
voltage equation
how a reaction that is thermodynamically unfavorable occur
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
exergonic reaction
products have less energy than reactants, spontaneous, graph will end lower than it started
if a reaction is kinetically favorable
it has k>1, relatively low activation energy
S = entropy
G = Gibbs free energy
H = heat energy
as V goes up, so does S
as the more temperature, the more energy, the mor entropy
spontaneous at all Temps, delta G <0
how do you calculate Gibbs free energy
delta G = delta H - (T * delta S)
gibbs free energy = enthalpy - (temperature times entropy)
*note T is in kelvin, not Celsius
delta S =
(sum of S products) - (sum of S reactants)
DO NOT FORGET TO ACCOUNT FOR THE MOLES IN THE REACTION!!!
cell potential, Ecell, electromotive force (emf)
2nd law of thermodynamics
what is Gibb's free energy
entropy
degrees of freedom of a molecule
delta G and the energy of the product is lower than that of the reactants
1. G = negative = k>1; G = positive = k
overall cell reaction
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
Cell potential equation
Ecell = E (cathode) - E (anode)
IMPORTANT: if the reaction gets reversed (in order to balance, sometimes it will need to be reversed), the sign of the Ecell must switch, however if it gets multiplied (in order to balance) IT REMAINS THE SAME!!
