MChem Master of Chemistry Materials Chemistry 3

Question 1

In lithium-ion batteries, what process occurs at the anode during charging?

Accepted Answer

Li+ ions are reduced and intercalated into graphite layers

Answer

Li+ ions are oxidized and released into the electrolyte

Answer

The electrolyte is oxidized at the carbon surface

Answer

LiCoO2 releases Li+ ions into the graphite

Question 2

What structural feature of metal-organic frameworks (MOFs) gives them among the highest surface areas of any known materials?

Accepted Answer

Their highly porous crystalline structures built from metal nodes connected by organic linkers

Answer

Their dense close-packed metal layers

Answer

Their amorphous disordered arrangement of metal atoms

Answer

Their multi-walled nanotube geometry

Question 3

What is the piezoelectric effect used for in materials chemistry applications?

Accepted Answer

Generating electric charge in response to mechanical stress, enabling sensing and actuation

Answer

Converting magnetic energy into electrical energy

Answer

Absorbing light to generate electricity in solar cells

Answer

Storing heat energy in phase-change materials

Question 4

What distinguishes a eutectic mixture from other alloy compositions?

Accepted Answer

It has the lowest melting point and solidifies as a microstructurally uniform mixture at a single temperature

Answer

It has the highest melting point of any composition in the system

Answer

It is a single-phase solid solution at all compositions

Answer

It undergoes incongruent melting, forming a different solid phase

Question 5

What is the principle behind quantum dot fluorescence tunability?

Accepted Answer

Quantum confinement causes the band gap to increase as nanoparticle size decreases, blueshifting emission

Answer

Different surface coatings absorb different wavelengths of light

Answer

Different crystal structures of the same material emit different colors

Answer

Surface defects trap electrons at fixed energy levels

Question 6

In polymer chemistry, what does the term 'living polymerization' refer to?

Accepted Answer

A controlled polymerization with no termination or chain transfer, allowing precise control of MW and architecture

Answer

A polymerization that only occurs in biological systems

Answer

A radical polymerization initiated by living organisms

Answer

A polymerization that continues indefinitely without initiator