9.8

What does electrochemistry encompass?

Study of redox reactions occurring within electrochemical cells

Are the redox reactions occurring within electrochemical cells thermodynamically favored or unfavored?

Either favored or unfavored

Do reactions that are thermodynamically favored result in a positive or negative voltage?

Positive

Do reactions that are thermodynamically unfavored result in a positive or negative voltage?

Negative

What do thermodynamically unfavorable reactions require for the reaction to proceed?

Externally applied potential

What must be identified in order to calculate the standard cell potential of electrochemical cells?

Oxidation and reduction half-reactions and their standard reduction potentials

A cell with a positive cell potential involves a thermodynamically favored or unfavored reaction?

Favored

A cell with a negative cell potential involves a thermodynamically favored or unfavored reaction?

Unfavored

Is the standard cell potential positive or negative in a galvanic cell?

Positive

Is the standard cell potential positive or negative in an electrolytic cell?

Negative

When combining two half-reactions to produce the overall equation for a redox reaction, what must be equal to what?

Number of electrons gained equal to number of electrons lost

What happens to sign of E if half reaction is reversed?

Reversed

What happens to value of E if half-reaction is multiplied by constant N?

No change

J/C = ?

V

What is joule a unit of?

Energy

What is coulomb a unit of?

Electric charge

If a half-reaction is multiplied by a constant N, what happens to joules and coulombs?

Multiplied by N

Why does cell potential value stay the same when half-reaction is multiplied by constant N?

Because both J and C are multipled by N so ratio of J/C remains the same so voltage (cell potential) remains the same

If standard cell potential is positive, is the standard free energy change positive or negative?

Negative

If standard cell potential is negative, is the standard free energy change positive or negative?

Positive

What does n in G=-nFE represent?

Number of moles of electrons transferred in overall balanced equation for the redox reaction