Quiz 3 (Mod 3, p. 1-13) Flashcards
define oxidation-reduction/redox reaction
chemical reaction in which transfer of electrons occurs
define oxidation number
charge that an atom has when electrons are counted
define oxidation
increase in oxidation nnumber through loss of electrons (OIL RIG)
define reduction
decrease in the oxidation number through gain of electrons (OIL RIG)
define oxidizing agent
accepts electrons
define reducing agent
donates electrons
define electrolytic cell
non-spontaneous electrochemical reactions are forced to take place by an external voltage on the cell (like by passing a current)
define galvanic cell
in which a chemical change takes place spontaneously with the production of electrical energy
what is a difference and similarity between the galvanic and electrolytic cells
similarity: reduction occurs at the cathode and oxidation occurs at the anode
difference: galvanic cells have positive cathode, electrolytic cells have negative cathode
define salt bridge
provides an “electrical” pathway between solutions in two half-cell without mixing of the solutions
what happens in redox titrations
an oxidizing agent is titration with a reducing agent or vice versa
how is the end of redox titrations determined?
colour change, specific indicator (ex. starch), redox indicator, potentiometric measurement
what is a potentiometer
an instrument that is designed to measure the difference in potential between an electrode (indicator electrode) that monitors the changes in the potential of the redox cell and an electrode (reference electrode) that is not involved i the redox reaction, without drawing appreciable electric current from the chemical system
What is a reference electrode and provide examples
reference electrode is the one that remains constant during the titration. ex.) standard hydrogen electrode (SHE), Calomel Electrode, Silver/Silver Chloride Electrode
