Aim 5: Electrochemical cells
Electrochemistry the branch of chemistry that
_______________is
studies the interchange of electrical and chemical
energy. It addresses:
-electricity producing a chemical rx or
a chemical rx
-_________________producing
electricity
(electrical energy)
There are 2 types of electrochemical cells:
a) ______________:
uses a chemical reaction to
the voltaic cell
produce electricity
the electrolytic cell uses electricity to produce a
b) _______________:
chemical reaction
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The Voltaic Cell
-The chemical reactions that produce electricity in
spontaneously
these cells occur_________________.
-Voltaic cells contain 2 half cells. ___________
The oxidation
half reaction
__________occurs
in one half cell while the
reduction half reaction occurs in the other half
cell.
-Each half cell contains an electrode and a salt
solution.
-an electrode is _____________________
a piece of metal that carries
a charge There are 2 different electrodes: the
________.
the voltaic cell the
_____
anode and the_______.
cathode In
______________,
cathode
______has
the positive charge and the ______has
anode
the negative charge.
RED CAT
AN OX
-the salt solutions found in the two different
a common (-) ion The other
half cells will contain___________.
(+) will be that of the electrode
ion___________________________.
Table J will tell you which piece of metal is the anode
and which is the cathode.
-The metal that is higher on the reactivity
is always the anode.
series_______________
-The metal that is lower on the activity series
is always the cathode
______________________.
Anode
B
Cathode
Oxidation
P
Q
Reduction
_______________________________________
2
Anode
-The metal that is the anode will always be
oxidized (lose e-).
_______________
are not oxidized the metal itself
-The ions in the cell______________,
is oxidized
_____________.
decrease
-The mass of this electrode (the anode) will ______
ions are falling off into solution as the
because the
________________________________
metal
becomes the ion
_____________________(by
losing its e-s).(the ions
have the protons and neutrons which are the two
subatomic particles that have mass)
-The concentration of the (+) ions in this half cell will
increase
more ions are falling into the solution.
________because__________________________
Cathode
ion in the reduction half cell will be _________
reduced
-The ___
cathode.
(by gaining e-s) at the________
reduced
-The cathode itself is not
_________
are reduced
not reduced the ions__________.
-The metal itself is__________;
increase
-The mass of this electrode (cathode) will _________
the ions start to "stick" to the cathode.
because_________________________________
-The concentration of the cations (+ ions) in this half
the ions are leaving the
decrease because __________________
cell will _________
solution
to reduce on the cathode
____________________________.
In the voltaic cell Zn/Zn2+//Pb2+/Pb the reaction that
occurs is:
The half reactions are:
Zn0
Zn2+ + 2ePb2+ + 2ePb0
0
Zn is the anode.
The _____
Pb2+ is the cathode.
The _____
Oxidation will occur at the _____________.
Anode
Zn0
_______
will be oxidized.
Reduction will occur at the _____________.
Cathode
Pb2+
_______
will be reduced.
3
In order for the electrons to transfer from the species
being oxidized (reducing agent) to the species being
reduced (oxidizing agent) they must travel across a wire.
-Electrons will always travel from
the anode (lose e-) to the ________________
cathode (gain e-).
_____________________
As the e- travel, the charge of the solutions would
become unbalanced. Something is needed to conserve
the charge.
salt bridge
-A ___________connects
the two half cells and
provides a path for the flow of ions between the two
the
migration of ions"). A
("allows for ______________________
cells ___________
__________contains
a salt (other than those used in
salt bridge
the two half cells) in which:
cathode and
-cations (+ ions) flow to the _________
-anions (- ions) flow to the __________
anode
the wire.
-e-carry a charge through __________
salt bridge.
-ions carry a charge through the ____________
Mark Rosengarten:You Start at the Anode
The Electrolytic Cell
-electrical energy is converted into chemical energy
-the chemical reactions that are produced in electrolytic
cells are NOT spontaneous
-in an electrolytic cell the anode is + and the cathode is -unlike a voltaic cell, the electrolytic cell has only one
chamber
anode
-oxidation still occurs at the ____________
cathode
-reduction still occurs at the ____________
(RED CAT
AN OX)
anode
-electrons still travel from the ___________
to the
wire
cathode
__________
along a ____________
4
The power source supplying the electrical energy acts as
an electron pump. It pulls the e- away from one
electrode and pushed them towards the other. The
positive terminal of the power source is connected to
the anode. This is what pulls the e- away. The negative
terminal of the power source is connected to the
cathode. Once the power source has pulled all of those
e- away from the anode, the e- are repelled and pushed
out towards the cathode.
reduced
-cations (+ ions) still _________at
the cathode
-anions (- ions) are __________at
the anode
oxidized
-Electroplating is performed via an electrolytic cell.
The object to be plated is the cathode. This allows
the positive ions from the metal you wish to plate with
to reduce on the cathode. The metal used for plating
is the anode.
Mark Rosengarten: Electrolysis is Smart
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