Chapter 12: Flashcards
(20 cards)
Define the current supplied by an electrochemical cell:
The rate of the movement of an electron from a anode to cathode.
Which law states that current is inversely proportional to resistance?
Ohm’s law - Delta V = IR
In a circuit with a lightbulb, what is the most effective way to increase the current flowing through the circuit?
Decrease the resistance.
Equation for net cell potential:
Ecell = Ecathode - Eanode
The ___________ will have a higher reduction potenital and will get ___________. The _________ will have a lower reduction potential and get ___________.
a. Anode; reduced; cathode; oxidized.
b. Cathode; reduced; anode; oxidized.
c. Cathode; oxidized; anode; reduced.
B - cathode; reduced; anode; oxidized
As something is reduced (at the cathode often), it will:
a. Lose electrons.
b. Lose ions.
c. Gain mass.
d. Ions will be plated onto the anode.
C - gain mass.
What does it mean for something to be electroplated onto the cathode?
It means that the metal ions are getting reduced, making them gain mass, and stick to the cathode - not move to the anode.
Define a salt bridge:
A salt bridge is made of an inert salt that will function as a conductor between a cathode and an anode
Do all galvanic cells require a salt bridge?
No!
Give an example of a galvanic cell that would not require a salt bridge:
A gravity cells, where the cathode and anode share the same solution. Because the solution will act as the conductor, there is no need for a salt bridge between the cathode and anode.
Define a galvanic cell:
A galvanic cell is an electrochemical cell that uses spontaneous redox reactions to create electrical energy. These are also called a voltaic cell. These will have a negative gibbs free energy, and a positive electromotive force.
True or false: Electromotive force and gibbs free energy of an electrochemical cell will always have the same sign.
FALSE - The electrochemical force is always the opposite sign of gibbs free energy.
The delta G for a galvanic cell is:
a. Always positive.
b. Always negative.
c. Always equal to 0.
d. Can be positive or negative depending on what ion is used.
b- always negative - these use spontaneous redox reactions.
What do we call the process of an ion getting reduced and precipitating on the cathode of a galvanic cell?
Galvanization or plating.
The delta G for an electrolytic cell is:
a. Always positive.
b. Always negative.
c. Always equal to 0.
d. Can be positive or negative depending on what ion is used.
a - always positive.
Define an electrolytic cell:
These electrochemical cells are driven by an energy input from electrolysis - the process of chemical compounds decomposing. This cell will have a positive Gibbs free energy (Non-spontaneous) and a negative electromotive force.
What is Faraday’s constant and when do you use it?
The amount of charge contained in 1 mole of electrons, equal to 10^5 Farads. This is used to calculate the number of mols being deposited on a plate in a cell - using this equation:
Mol = (IT)/(nF)
I = current.
T = time.
n = number of electrons.
F = Faraday’s constant.
Define a concentration cell:
A concentration cell is a type of galvanic cell - with a spontaneous redox reaction between a cathode and anode. However, this differs from a regular galvanic cell because both the cathode and anode will use the same metal - with the same reduction potential - so current is established due to a concentration difference between 2 compartments.
Define a rechargeable battery:
A battery that can function as both a galvanic and electrolytic cell.
