14.2 Flashcards
What are galvanic cells or voltaic cells?
Electric cells adapted for scientific study
How do electrons move in a voltaic cell?
Electrons move from the reducing agent to the oxidizing agent through an external circuit rather than directly to each other
What does a porous boundary do?
Separates the two electrolytes while permitting ions to move between the two solutions through tiny openings in the cotton plugs of the salt bridge
What can each part of a cell be split into?
A half cell
What does a half cell consist of?
One electrode and one electrolyte
What is a voltaic cell?
An arrangement of 2 half cells separated by a porous boundary
What happens to the strongest oxidizing agent in a voltaic cell?
It undergoes reduction at the cathode
What happens to the strongest reducing agent in a voltaic cell?
They give up electrons in an oxidation half reaction and enter the solution at the anode
What is the cathode in relation to oxidation and reduction?
The cathode is the electrode where the reduction occurs
What is the anode in relation to oxidation and reduction?
The anode is the electrode where the oxidation occurs
What do inert electrodes do?
Provide a location to connect a wire and a surface on which a half reaction can occur
What is standard cell potential?
The maximum electric potential difference (voltage) of the cell operating under standard conditions
What is a standard cell?
A voltaic cell in which each half-cell contains all entities shown in the half reaction equation at SATP conditions
What is standard reduction potential?
The ability of a standard half cell to attract electrons, thus undergoing reduction
Which half-cell gains the electrons?
The half cell with the greater attraction for electrons (the one with the more positive reduction potential)
How can standard cell potential be calculated?
Ecell = Er (cathode) - Er (anode)
Why is it impossible to determine the reduction potential of a single half cell?
Because electron transfer requires both an oxidizing agent and a reducing agent
What is a reference half-cell?
A half-cell that is chosen as a reference and arbitrarily assigned an electrode potential of zero volts (hydrogen)
What does the standard hydrogen half-cell consist of?
An inert platinum electrode immersed in hydrogen ions with hydrogen gas bubbling over the electrode
What is the reduction potential of hydrogen?
0.00 Volts
What does it mean when a reduction potential has a positive value?
The oxidizing agent agen is the stronger agent than hydrogen ions are
What does a negative reduction potential mean?
That the oxidizing agent is weaker oxidizing agent than hydrogen ions
What cell potential indicates that a reaction is spontaneous?
A cell potential greater than 0
What happens as a cell is used continuously for a long time?
The electrical potential difference decreases as the cell operates. Eventually the voltage becomes zero
