How do you calculate the standard cell potential (E°cell) for a reaction at 25°C?
To calculate the standard cell potential (E°cell) at 25°C, subtract the standard reduction potential of the anode from that of the cathode: E°cell = E°(cathode) - E°(anode). Use standard conditions (1 M, 1 atm, pH 7) and ensure you identify which half-cell is the cathode (higher E°red) and which is the anode (lower E°red). A positive E°cell indicates a spontaneous (galvanic/voltaic) cell.
What are the standard conditions required when measuring standard cell potential (E°cell)?
Standard conditions are 1 M concentration for ions, 1 atm pressure, and pH 7.
What physical quantity does the unit 'volt' (V) represent in the context of cell potential?
Volt represents the amount of work done per unit charge as electrons move between electrodes; it is equivalent to joules per coulomb (J/C).
What is the SI unit for electric charge, and what symbol is used for it?
The SI unit for electric charge is the coulomb, represented by the symbol 'C'.
In a galvanic (voltaic) cell, which compartment has the higher standard reduction potential?
In a galvanic cell, the cathode compartment has the higher standard reduction potential.
What does a negative standard cell potential (E°cell < 0) indicate about the reaction?
A negative E°cell indicates the reaction is non-spontaneous, typical of an electrolytic cell.
How do the roles of cathode and anode differ between galvanic and electrolytic cells regarding standard reduction potential?
In galvanic cells, the cathode has the higher E°red; in electrolytic cells, the cathode has the lower E°red.
What is the relationship between the type of electrochemical cell and the sign of E°cell?
Galvanic cells have E°cell > 0 (spontaneous), while electrolytic cells have E°cell < 0 (non-spontaneous).
Why is it important to correctly identify the cathode and anode when calculating E°cell?
Correctly identifying the cathode and anode ensures the proper application of the formula and accurate determination of cell spontaneity.
What are the two main types of electrochemical cells discussed in relation to standard cell potential?
The two main types are galvanic (voltaic) cells and electrolytic cells.