Redox Reactions & Simple Galvanic Cells

Flashcards summarise key ideas on redox reactions, galvanic cell structure, operation, historical context, battery types, and environmental considerations.

What form of energy is released during a spontaneous exothermic redox reaction?

Heat energy.

Which everyday power sources rely on redox reactions to generate electricity for mobile devices?

Rechargeable batteries (galvanic/voltaic cells).

What is the overall redox equation when zinc metal reacts with copper(II) sulfate solution?

Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s).

In the Zn–Cu galvanic cell, electrons flow from which metal to which metal ion?

From zinc metal to copper(II) ions.

What is the primary function of the salt bridge in a galvanic cell?

To complete the circuit by allowing ions to migrate between half-cells and maintain electrical neutrality.

Define a galvanic (voltaic) cell.

An electrochemical cell that converts chemical energy from a spontaneous redox reaction into electrical energy.

What two components must every half-cell contain?

An electrode (solid conductor) and an electrolyte (ion-conducting solution).

In cell notation, how is a copper half-cell written?

Cu(s) | Cu²⁺(aq).

Where does oxidation occur in a galvanic cell?

At the anode.

Where does reduction occur in a galvanic cell?

At the cathode.

Which electrode is negative in a galvanic cell?

The anode (where electrons originate).

Which electrode is positive in a galvanic cell?

The cathode (where electrons are consumed).

In a Cu(s)/Cu²⁺||Ag⁺/Ag(s) cell, which species is oxidised?

Copper metal (Cu) is oxidised to Cu²⁺.

In the same Cu–Ag cell, which species is reduced?

Silver ions (Ag⁺) are reduced to Ag(s).

Complete the oxidation half-equation for zinc in a galvanic cell: Zn(s) →

Zn²⁺(aq) + 2e⁻.

Complete the reduction half-equation for copper(II) ions: Cu²⁺(aq) + 2e⁻ →

Cu(s).

How does the reactivity series help predict reactions in galvanic cells?

The metal lower (stronger reducing agent) is oxidised; its ions’ partner in the other half-cell is reduced.

Electron flow direction in the external circuit of any galvanic cell is always .

From anode (negative) to cathode (positive).

What is a primary cell?

A disposable electrochemical cell designed for single-use; not rechargeable.

What is a secondary cell?

A rechargeable electrochemical cell designed for repeated discharge and recharge cycles.

Main electrolyte difference between a traditional dry cell and an alkaline cell?

Dry cell uses an acidic electrolyte; alkaline cell uses an alkaline (basic) electrolyte.

Give two key reasons for recycling used batteries.

Recover non-renewable metals and prevent toxic metals (e.g., lead, mercury) from leaching into the environment.

Who observed frog‐leg twitching due to electricity between two different metals?

Luigi Galvani.

Who constructed the first ‘voltaic pile’ battery and has the volt named after him?

Alessandro Volta.

What is a ‘crown of cups’ battery?

A series of simple galvanic cells connected in series to increase voltage, first demonstrated by Volta.

In a salt bridge, ions move so that negative ions travel in the same direction as .

Electrons (through the external circuit).

Memory aid linking electrode and reaction types in cells.

‘AnOx, RedCat’ – Oxidation at the Anode, Reduction at the Cathode.

Which metal acts as the reducing agent in a Zn(s)/Zn²⁺ || Pb²⁺/Pb(s) cell?

Zinc metal (Zn).

Define the term “battery” in strict electrochemical language.

A series of two or more electrochemical cells connected together.

Why are modern secondary-cell batteries vital for renewable energy adoption?

They store energy efficiently, enabling devices like electric vehicles and grid storage to utilize intermittent renewable sources.