book!! Flashcards
what interconversion does it electrochemistry deal with
interconversion of electrical energy and chemical energy
how do electrical effects occur
due to the movement of electrical charge
either ions in solution or electrons in a conductor
electrical current definition
the rate at which a charge passes a point
symbol for electrical current
I
symbol for current
A (amperes)
what must be present for an electrical current to flow between 2 points in a circuit
potential difference (VOLTAGE) between the 2 points
what is the potential difference
the driving force that pushes electrons // ions around the circuit
what is potential difference measured in
Volts
V
what law relates current and potential difference
ohms law
V = I x R
what is R in ohms law
the resistance of the material that the current is flowing through
what is resistance measured in
measured in ohms
what does a higher resistance mean
it means it’s harder for the charge to flow through the material
how does current affect voltage in an electrochemical cell
a high current leads to a loss in voltage??
as the reactants are used up
how does a large resistance affect current and voltage
a larger resistance decreases current and voltage.
voltage doesn’t decrease as fast tho!!
high current means
voltage falls quick
reactants are used up fast
large resistance means
voltage falls slower
reactants are used up slower
current is low
high resistance in terms of voltage
high resistance = max voltage
very very small current
what is max voltage called
zero current cell potential
electromotive force (emf)
Ecell
high resistance ====
max voltage ( emf)
nearly no current
simple electrochem system:: zinc metal in copper (||) sulphate
zinc dissolves
copper solid is formed
solution changes from blue to colourless (lack of copper in solution due to it forming a solid from gaining 2 e-)
what equations are present in electrochem chem reactions
half reactions!!
one shows oxidation (loss of e-)
one shows reduction (gain of e-)
what reactions are seen in electrochem chem
half reactions
what are half reactions
one shows reduction ( gain of e-)
one shows oxidation (loss of e-)
what a redux reaction
when oxidation and reduction occur simultaneously
what happens on the surface of a metal in electrochem cells
electron transfer::
metal dissolves and forms an ion (losing e-)
ions in solution gain these e- to form a metal (seen on the surface)
what interconversion electrochem chemistry involve
interconversion of chemical and electrical energy
how can charge be moved by e- transfer
through conductors
ion transport in solution
max voltage in a cell
Ecell
EMF
zero current cell potential
