Redox Rxns Quiz Flashcards
compare and contrast galvanic/voltaic cells with electrolytic cells
both cells have anodes and cathodes and electrolytes. both anodes lose mass and cathodes gain mass. galvanic cell has a positive cell potential and the electrolytic cell a negative cell potential. the electrolytic cell requires a power source.
purpose of a salt bridge
it keeps the soln from polarizing and maintains ionic balance
how do e° cell values differ between voltaic and electrolytic cells
voltaic cells have positive e° cell values and electrolytic have negative cell values
what is the purpose of the graphite or platinum electrodes in an electrochemical cell
both are chemically inert and provide a surface for gaseous oxidizing and reducing agents to react
which was does the KCl travel to
K+ -> anode, Cl- ->cathode
electrochemical cell
aka the voltaic cell or a Galvanic cell; portable source of electricity produced from a spontaneous redox rxn
components of a electrochemical cell
- 2 electrodes
- 2 chambers(filled with electrolyte solns)
- salt bridge
- conductor
anode
electrode where oxidation occurs
cathode
electrode where reduction occurs
salt bridge
u-tube filled with an electrolyte that allows for ion migration and completes the circuit
conductor
wire that connects the anode to the cathode with a voltmeter attached
electrochemical cell: overall voltage voltage value
overall voltage is positive and the voltage value is negative
Eo(cell)=
Eo(cathode)-Eo(anode)
standard cell potential(E° cell)
the difference in electric potential between half cells
E° cell and spontaneity
positive value=spontaneous
negative value=not spontaneous
gibbs free energy
the energy available to do work in a system(kJ); must negative to be spontaneous
standard gibbs free energy is proportional to
-negative value for E° cell
-moles of electrons in balanced half rxns
electrochemistry
the study of the exchange of electrical and chemical energy; reactions in electrochemistry are called oxidation-reduction reactions or redox runs and involve the exchange of electrons
metathesis rxns
rxns that don’t transfer electrons; usually types of double displacement reactions
reduction
the process of gaining an electron and lowering the oxidation number
oxidation
the process of losing an electron and increasing the oxidation number
oxidizing agent
reactant that gets reduced in a reaction
reducing agent
reactant that gets oxidized in a reaction
disproportionation reaction
reaction where one species is both the reducing agent and oxidizing agent
SRP table
table used to predict if a chemical species will spontaneously donate or accept electrons from another
the strength of an oxidizing agent is called its
reduction potential; this measures the oxidizing agent’s potential to be reduced, not to reduce
the strength of the reducing agent is called its
oxidation potential; this is found by changing the positive or negative sign change of Eo
single displacement reaction
reaction where a chemical species replaces another in a camped if it is more reactive
activity series
list of elements in order of reactivity; derived from the SRP table
Faraday’s constant
96,485 C/mol e-
electrolysis
the conduction of a current through an electrolyte
electrolysis eqn
I=q/t
ampere=
coulomb/second
q=
amount of charge(coulombs)
t=
time(seconds)
electroplating
type of electrolysis where metal ions in soon are plated onto an object using a current
