Handout 13-4 Voltaic Cell

A voltaic cell spontaneously converts

• electrical energy to chemical energy

• chemical energy to electrical energy

• electrical energy to nuclear energy

• nuclear energy to electrical energy

Answer explanation

A voltaic cell converts chemical energy stored in reactants into electrical energy through spontaneous redox reactions, making 'chemical energy to electrical energy' the correct choice.

Tags

NGSS.HS-PS3-2

In an operating voltaic cell, reduction occurs

• at the anode

• at the cathode

• in the salt bridge

• in the wire

Answer explanation

In a voltaic cell, reduction occurs at the cathode, where electrons are gained. The anode is where oxidation takes place, while the salt bridge and wire facilitate ion and electron flow, respectively.

Which change occurs at the anode in an operating electrochemical cell?

• gain of protons

• gain of electrons

• loss of protons

• loss of electrons

Answer explanation

In an operating electrochemical cell, the anode is where oxidation occurs, leading to the loss of electrons. This is why the correct answer is 'loss of electrons', as electrons are released into the circuit.

Which half-reaction can occur at the anode in a voltaic cell?

• Ni2+ + 2e- → Ni

• Sn + 2e- → Sn2+

• Zn → Zn2+ + 2e-

• Fe3+ → Fe2+ + e-

Answer explanation

The half-reaction Zn → Zn2+ + 2e- occurs at the anode in a voltaic cell because it represents oxidation, where zinc loses electrons. The other options involve reduction or do not fit the anode process.

When a voltaic cell operates, ions move through the

• anode

• cathode

• salt bridge

• external circuit

Answer explanation

In a voltaic cell, ions move through the salt bridge, which connects the two half-cells and allows for the flow of ions to maintain charge balance, enabling the cell to operate effectively.

What is the purpose of the salt bridge in a voltaic cell?

• It blocks the flow of electrons.

• It blocks the flow of positive and negative ions.

• It is a path for the flow of electrons.

• It is a path for the flow of positive and negative ions.

Answer explanation

The salt bridge in a voltaic cell allows the flow of positive and negative ions between the half-cells, maintaining electrical neutrality and completing the circuit, which is essential for the cell's operation.

Tags

NGSS.HS-PS2-5

Given the balanced ionic equation representing the reaction in an operating voltaic cell: Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) The flow of electrons through the external circuit in this cell is from the

• Cu anode to the Zn cathode

• Cu cathode to the Zn anode

• Zn anode to the Cu cathode

• Zn cathode to the Cu anode

Answer explanation

In a voltaic cell, oxidation occurs at the anode and reduction at the cathode. Here, Zn is oxidized to Zn2+ (anode) and Cu2+ is reduced to Cu (cathode). Therefore, electrons flow from the Zn anode to the Cu cathode.

Which species is oxidized when the switch is closed?

• Mg(s)

• Mg2+(aq)

• Ag(s)

• Ag+(aq)

Answer explanation

When the switch is closed, Mg(s) is oxidized as it loses electrons to form Mg2+(aq). Oxidation involves the loss of electrons, and in this case, solid magnesium is the species undergoing oxidation.

Tags

NGSS.HS-PS1-2

When the switch is closed, electrons flow from

• Mg(s) to Ag(s)

• Ag(s) to Mg(s)

• Mg2+(aq) to Ag+(aq)

• Ag+(aq) to Mg2+(aq)

Answer explanation

When the switch is closed, electrons flow from Mg(s) to Ag(s) because magnesium is more reactive and loses electrons, while silver gains them. This movement of electrons is essential in electrochemical reactions.

Tags

NGSS.HS-PS1-2

NGSS.HS-PS2-5

Which species represents the cathode?

• Mg

• Mg2+

• Ag+

• Ag

Answer explanation

In electrochemistry, the cathode is where reduction occurs. Ag (silver) is reduced from Ag+ ions, making it the cathode. Mg and Mg2+ are involved in oxidation, not reduction, so they do not represent the cathode.