Unit 3 Chapter 6: Galvanic cells Flashcards
Galvanic cell (voltaic cell) (out of 6):
- produces electricity
- Spontaneous reaction
- Chemical energy –> electrical energy
- Anode is negative and cathode is positive
- Oxidation occurs at the anode and Reduction occurs at the cathode
- Electrons flow from anode to cathode
Electrochemical cell:
device in which chemical energy is converted into electric energy, or vice versa
Battery:
combination of cells connected in series to obtain a higher potential difference (voltage)
Galvanometer:
instrument used to detect electric current
Salt bridge:
contains ions that are free to move so they can balance charged formed in the two half-cells. Cations from the salt bridge move toward the cathode and anions move toward the anode
Spontaneous reaction:
occurs naturally
Half-cell:
galvanic cells consist of two-half cells, each with an electrode in contact with solution
Standard hydrogen electrode (SHE):
used as standard reference half-cell with value of 0
Standard electrode potential/reduction potential (E°):
measured by connecting half-cell to SHE and measuring voltage
- Gives a numerical measure of the tendency of a half-cell reaction to occur as a reduction reaction
- Used as basis of electrochemical series
Electrochemical series:
half-reactions listed from strongest reducing agent (most likely to be oxidised, most negative E° value) to the strongest oxidising agent (most likely to be reduced, most positive E° value)
- these are valid under standard conditions
Cell potential difference:
= E° (oxidising agent) – E° (reducing agent)
= E° (oxidising agent) – E° (reducing agent)
For a spontaneous reaction to occur, an oxidising agent must react with a reducing agent that is higher in the series… True or False?
True
Half-cell with higher E° value (out of 2):
- Reduction occurs
- Positive electrode
Half-cell with lower E° value (out of 2):
- Oxidation occurs
- Negative electrode
When reactants react in a galvanic cell, chemical energy converts to:
electrical energy
