ELECTROLYSIS AND ELECTROCHEMICAL CELL FLASHCARDS

Cathode Reaction in Electrolysis

Reduction occurs at the cathode because positively charged ions gain electrons there.

Faraday's First Law (Current Effect)

The mass deposited is directly proportional to current when time is constant; doubling current doubles the mass deposited.

Agricultural Water Pollution Reduction

Controlled and proper application of fertilizers and pesticides minimizes agricultural runoff into water bodies.

Role of Vegetation Around Water Bodies

Vegetation reduces soil erosion and acts as a filter to trap pollutants before they enter aquatic systems.

Electrode

A conductor through which electric current enters or leaves an electrolyte.

Electron Flow in Galvanic Cells

Electrons flow through the external circuit from the anode to the cathode.

Faraday's First Law of Electrolysis

States that the mass of a substance deposited during electrolysis is directly proportional to the quantity of electricity passed ($Q = I \times t$).

Strong Electrolyte

A substance, such as sodium chloride ($NaCl$), that ionizes completely in aqueous solution.

Galvanic vs. Electrolytic Cells

Galvanic cells convert chemical energy into electrical energy, while electrolytic cells use electrical energy to drive non-spontaneous chemical reactions.

Anode in Electrolytic Cells

The electrode connected to the positive terminal of a direct-current source where oxidation takes place.

Lead Contamination

A toxic heavy metal that poses severe human health risks when present in contaminated water supplies.

Reduction in Zinc-Copper Galvanic Cell

Copper ions ($Cu^{2+}$) gain electrons at the copper electrode and are reduced to solid copper metal ($Cu$).

Quantity of Electricity Calculation

Calculated using $Q = I \times t$. For $I = 5\,A$ and $t = 20\,\text{minutes}$, $Q = 5 \times (20 \times 60) = 6000\,C$.

Oxidation and Reduction Sites

The anode is always the site of oxidation and the cathode is always the site of reduction in both galvanic and electrolytic cells.

Electroplating

An application of electrolytic cells that uses electrical energy to deposit a metal layer onto a surface.

Oil Pollution Control

Containment barriers prevent oil from spreading, allowing cleanup methods to remove spilled oil from water bodies.

Industrial Effluents

Discharges from factories that serve as major sources of water pollution by introducing heavy metals and harmful chemicals.

Energy Conversion in Electrolytic Cells

Converts electrical energy into chemical energy during forced chemical changes.

Environmental Impact of Oil Spills

Forms a surface layer on water that hinders gas exchange, disrupting aquatic life and ecosystems.

Purpose of Electrolysis

To utilize electrical energy to drive chemical decomposition or chemical transformations.