Ch. 12 Flashcards
what is oxidation state/number? what do you call a rxn that changes OS?
OS shows how many electrons it is donating or accepting in the overall bonding. a rxn that goes through this is called a oxidation-reduction (redox) rxn
what is oxidation? reduction?
oxidation: gain of O, loss of electrons, loss of hydrogens
reduction: loss of O, gain of electrons, gain of hydrogens
atom that is oxidized is called?
reducing agent/reductant
atom that is reduced is called?
oxidizing agen/oxidant
the flow of electrons means that
an electric current that can do work
redox rxns can make an electrical current through what cell
galvanic (voltaic) cell
what occurs in a galvanic (voltaic) cell
theres two electrodes (anode and cathode) with a wire that measures EC connecting both electrode and a salt bridge as well
what electrode gets oxidized and reduced? in what direction does electrons travel to in galvanic cell
anode always gets oxidized and cathode always gets reduced. in a galvanic cell, electrons travel to cathode
a redox reaction will be spon if cell voltage is
(+)
what is reduction potential
its a value you can calculate cell voltage by adding the two half rxns
what does - reduction potential
the more (-) the RP, the weaker the reactant is as oxidizing agent and stronger the product is as a reducing agent
what does + reduction potential
the more (+) the RP, the stronger the reactant is as oxidizing agent and weaker the product is as a reducing agent
what is a electrolytic cell
uses an external voltage source like a battery to create an electric current that forces a nonspon rxn to occur this is electrolysis
what are the charges of the electrodes in a electrolytic cell
anode is + and cathode is - since electrons are moving where they dont want to go because nonspon
similarities between electrolytic cell and galvanic cell
- reduction at cathode
- oxidation at anion
- anions migrate to anode
- cations migrant to cathode
differences between electrolytic cell and galvanic cell (electrolytic cell only) describes galvanic
electrolytic: 1. spon rxn generates EC
2. total energy is (+)
3. anode is -
4. cathode is +
differences between electrolytic cell and galvanic cell (galvanic cell only)describe electrolytic
- nonspon needs external source
- total e is (-)
- anode is +
- cathode is -
what is faradays law of electrolysis
the amount of chemical changes is proportional to the amount of electricity that flows through the cell
a charge separation where anode becomes (+) and cathode becomes (-), what does this resemble?
capacitor
what is a cell diagram
shows the anode[anodic solution] cathodic solution] cathode
more negative E means?
product is strong reducer while reactant is weak oxidizer
more positive E means?
product is weak reducing agents while reactant is strong oxidizer
what does Nernst eq show?
shows how changes in temp and conc of reactants can alter the voltage of a rxn NOT in standard conditions
what is a concentration cell?
galvanic cells with identical electrodes in solutions of diff ion conc, they ract until the solutions become the same ion conc
what is a rechargeable battery
uses oxidation states of Pb and sulfuric acid as electrolyte
what is faradays law of electrolysis
amount of chemical change is proportional to amount of electricity that flows through cell
low ionization energy means
better reducing agent
a strong oxidizing agent will have a high
oxidation state because it can be reduced all the time
electrons will always flow from
anode to cathode
if you have a galvanic cell with two half reactions and one is negative what do you need to do?
reverse equation to have positive reduction potential to then make the accurate redox eq
