Electrochemistry Unit 20 Quiz

In an electrochemical cell, electrons are generated at the

• anode.

• cathode.

• circuit.

• electrolyte.

What is used to keep two half-cells apart but allow charges to flow?

• an electrolyte

• a cathode

• a porous barrier

• an anode

Where does oxidation take place in an electrochemical cell?

• the anode

• the cathode

• the anode or the cathode

• the half-cell

The oxidation number of the substance taking part in the reaction that occurs at the cathode

• decreases.

• increases.

• does not change.

• None of the above

In an electrochemical cell, the cathode is the

• neutral electrode.

• electrode at which matter can gain or lose electrons.

• electrode at which matter gains electrons.

• electrode at which matter loses electrons.

For an electric current to exist in an electrochemical cell, the two half-cells must be

• connected to a dry cell.

• in the same solution.

• completely isolated from one another.

• connected by a wire and a porous barrier.

What is the cell notation for the following net reaction? Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s)

• Zn(s)|Cu2+(aq)||Zn2+(aq)|Cu(s)

• Zn(s)|Zn2+(aq)||Cu2+(aq)|Cu(s)

• Zn2+(aq)|Zn(s)||Cu2+(aq)|Cu(s)

• Zn(s)|Cu(s)||Zn2+(aq)|Cu2+(aq)

If the reactants in an electrochemical cell are in contact, __________________.

• most of the energy is released as an electric current.

• hydrogen gas is released.

• oxidation and reduction do not occur.

• most of the energy is released as heat.

In the electrochemical cell shown above, in which direction will positive ions flow?

• from B to A

• from A to B

• from the anode to D

• from the cathode to D

Consider the following cell notation: Mg(s)|Mg2+(aq)||Cu2+(aq)|Cu(s) What is the half-reaction at the anode?

• Cu2+(aq) + 2e- ----- Cu(s)

• Cu(s) ----- Cu2+(aq) + 2e-

• Mg2+(aq) + 2e- ----- Mg(s)

• Mg(s)------ Mg2+ (aq) + 2e-