Untitled Quiz

Galvanic Corrosion

• Occurs when two dissimilar metals are in contact in the presence of an electrolyte.
• The metal with a more negative standard reduction potential will corrode preferentially.

Aluminum Corrosion

• Aluminum has a greater tendency to corrode than iron but does not suffer problematic corrosion.
• Aluminum oxide (Al2O3) forms a protective layer that prevents further corrosion.

Iron Corrosion

• Iron corrodes continuously because the iron oxide (rust) layer is porous and does not protect the underlying metal.

Corrosion

• Corrosion is the degradation of metals by chemical reactions with their environment.

Crevice Corrosion

• Crevice corrosion occurs in small gaps between two pieces of metal due to the concentration of corrosive species within the confined space.

Redox Reactions

• Reactions involving the transfer of electrons between reactants are called redox reactions.

Rust Formation

• Rust forms through a complex series of electrochemical reactions.
• It involves the oxidation of iron to iron ions and the reaction of these ions with oxygen and water to form hydrated iron oxide (rust).

Batteries

• It is important to distinguish between primary and secondary batteries because primary batteries are not rechargeable, while secondary batteries are.

Salt Bridge

• The primary role of the salt bridge in a galvanic cell is to maintain electrical neutrality by allowing the flow of ions between the half-cells.

Ion Flow

• When using a salt bridge with NH4Cl, the NH4+ ion flows into the Ag+ half-cell.

Cell Notation

• In the cell notation for a galvanic cell, the double vertical line (||) represents the salt bridge or other porous barrier separating the half-cells.

Anode

• The anode in a galvanic cell is the electrode where oxidation occurs.

Galvanic Cell Potential

• The voltage potential for a galvanic cell described with Cu and Ag is +0.46 V.

Standard State

• An electrochemical cell is considered to be in its standard state when all reactants and products are at a concentration of 1 M and the temperature is 25°C.

Oxidation

• When oxidation occurs at the anode, electrons are released and flow through the external circuit to the cathode.

Electrodes

• Electrodes in galvanic cells are typically made of metals or other conductive materials.
• They provide a surface for the redox reactions to take place.

Cathode

• The cathode in electrochemical processes is the electrode where reduction occurs.

Lithium-Ion Battery (LIB)

• The Dreamliner's need for LIBs is due to their high energy density and lightweight design.

Cell Potential

• Cell potential or electromotive force (EMF) is defined as the potential difference between the two electrodes of an electrochemical cell.

Lithium-Ion Battery Electrodes

• The primary materials used in the electrodes of LIBs are lithium compounds, such as lithium cobalt oxide (LiCoO2) and graphite.

Salt Bridge Absence

• If a salt bridge is not present in an electrochemical cell, the cell will not function properly.
• Without the salt bridge, the buildup of charge in the half cells would create a potential difference that would prevent the flow of electrons.

Lithium Battery Energy Density

• Lithium's high energy density in LIBs is attributed to its low atomic weight and high electrochemical potential.

Tin Plating in Galvanic Corrosion

• Tin plating serves as a protective layer on steel.
• When exposed to air and moisture, tin, being more anodic than steel, corrodes preferentially, protecting the steel underneath.

Uniform Corrosion

• Uniform corrosion describes the even, gradual corrosion of a metal surface.

Lithium-Ion Battery Temperature

• High temperatures can degrade LIBs by accelerating chemical reactions and causing electrolyte decomposition.

Iron Corrosion in Water

• For iron corrosion to occur in water, the presence of an electrolyte (such as dissolved salts) and oxygen is necessary.

Carbon in LIBs

• Carbon plays a vital role in LIBs, acting as the anode material.
• It provides a framework for lithium ions to intercalate and deintercalate during charging and discharging.

Plated Steel Corrosivity

• The corrosivity of different plated steels can be determined by using standard electrochemical techniques like the Tafel extrapolation method or cyclic voltammetry.

Scratched Tin-Plated Steel

• When exposed to air and moisture, a scratched tin-plated steel can will show localized corrosion at the scratch.
• The steel will corrode preferentially at the exposed area because tin is more anodic than steel.

Voltmeter Measurement

• A voltmeter measures the potential difference between two points in an electrical circuit.

Battery Poles Reversal

• Reversing the poles of a battery will reverse the voltage reading on a voltmeter.

Standard Hydrogen Electrode (SHE)

• The SHE is assigned a standard potential of 0.00 V.

SHE Half-Cell Notation

• The half-cell notation for the SHE is Pt(s) | H2 (g, 1 atm) | H+ (aq, 1 M).

Standard Cell Voltages

• Measurement of стандартных стандартных потенциалов указывает на то, что каждая полуреакция имеет стандартный потенциал независимо от других полуреакций, которые могут быть объединены с ней.

SHE in Galvanic Cells

• The SHE can serve as either the cathode or anode in a galvanic cell, depending on its connection to the other half-cell.

Oxidation in Galvanic Cells

• In a galvanic cell, oxidation always occurs at the anode, and the electrons flow from the anode to the cathode.

Anode to Voltmeter Positive Terminal

• Connecting the anode to the positive terminal of a voltmeter will result in a positive voltage reading.

Cathode Role

• The cathode in an electrochemical cell is the electrode where reduction occurs.
• It gains electrons from the anode through the external circuit.

Positive Potential with SHE

• A positive potential when the SHE is connected to the positive terminal indicates that the other half-cell has a higher standard reduction potential than the SHE.

Reversed Voltmeter Leads

• If the leads of the voltmeter are reversed, the reading will change sign but maintain the same magnitude.

Standard Reduction Potentials

• Standard reduction potentials are typically represented as E° values, where the value is negative or positive, indicating the tendency of the half-reaction to occur spontaneously as a reduction.

Oxidation Potential Conversion

• Converting a standard reduction potential to an oxidation half-reaction requires reversing the sign of the potential.

Negative Standard Reduction Potential

• A negative standard reduction potential indicates that the reaction prefers to occur as an oxidation, rather than a reduction.

Standard Reduction Potential Comparison

• The standard reduction potentials of half-reactions provide information about their relative tendencies to undergo reduction under standard conditions.
• Half-reactions with more positive standard reduction potentials are more likely to occur as reductions.

Electron Flow in Galvanic Cells

• The external circuit, connecting the anode and cathode in a galvanic cell, is responsible for the flow of electrons.
• Electrons flow from the anode (where oxidation occurs) to the cathode (where reduction occurs).