Chapter 17: Electrochemistry Flashcards
what is electrochemistry
a branch of chemistry that relates electricity and chemical reactions
what does the law of conservation of mass say
amount of each element must be the same on both sides
what can be used to balance the gains and losses of electrons
half reaction metod
what is oxidation
lose electrons (more positive)
what is reduction
gain electrons ( more negative)
what is the half reaction method
- write the oxidation and reduction as two separate processes
- balance the 1/2 reactions then combine them to attain the balanced equation for the overall reaction
if there is oxidation in a reaction where are the electrons
on the right (products)
if there is reduction where are the electrons in the rxn
electrons are on the left (reactants)
if a reaction occurs in a basic solution how do you balance it
balance it as if it occurred in an acid
what happens to the electrons in a spontaneous redox rsn
electrons are transferred and energy is released
why are redox reactions in energy
have the potential to generate electrical current
- use the energy to make the electrons go through an external device
what is another name for the voltaic cell
galvanic
in a voltaic cell, setup do the metals touch
the metals are not direct
why do we separate the reduction and oxidation half reactions
so that we can create a flow of electrons
what is the purpose of an electrode
electron flow though a wire with ion flow through a solution
what does electrode require
conductive solid electrode
what is an electrode
two solid metals connected by external circut
where does oxidation occur in a voltaic cell
anode
where does reduction occur in a voltaic cell
cathode
in the cell how do the electrons flow
leave the anode and flow through the wire to the cathode
what happens when the electrons leave the anode
cations formed dissolve into the solution in the anode compartment
- anode loses mass and the soln becomes more concentrated
what happens when electrons reach the cathode
cations in the solution the cathode is in are attracted to the now negative cathode
- cathode gains mass and the soln it is in becomes less concentrated
- electrons form neutral metals
what is a salt bridge
u shaped tube that contains a salt solution, to keep the charges balanced
what is the salt bridge composed of
ions that will not react with other ions in the cell or with the electrode materials
