Properties of Ceramics and Polymers Quiz

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Why are ceramics considered brittle materials?

Because they are always exposed to high temperatures

Because they have low density

As a result of their high electrical conductivity

Due to the presence of porosity (correct)

What process is used to produce polymers?

Polymerization (correct)

Fermentation

Distillation

Oxidation

Why are polymers typically not suitable for high-temperature applications?

Because they are too heavy

Because they have low strength at high temperatures (correct)

Because they lack resistance to corrosive chemicals

Due to their poor electrical resistivity

What distinguishes thermoplastics from thermosetting polymers?

The process of shaping: molding vs. casting Signup and view all the answers

What is a key characteristic of electronic materials like silicon and gallium arsenide-based semiconductors?

Semiconductor behavior Signup and view all the answers

What is a common application of plastics according to the text?

Bulletproof vests and compact disks Signup and view all the answers

Why are alkali and alkaline earth metals labeled as electropositive?

Because they give up electrons readily to form positively charged ions Signup and view all the answers

Which group in the periodic table includes transition metals?

Groups IIIB through IIB Signup and view all the answers

What is a characteristic of elements in groups IIIA, IVA, and VA in terms of their valence electron structures?

They display intermediate characteristics between metals and nonmetals Signup and view all the answers

What term is used to describe elements on the right side of the periodic table?

Electronegative Signup and view all the answers

According to Figure 2.9, how does electronegativity change when moving from left to right in the periodic table?

It increases Signup and view all the answers

In terms of electronegativity values, how does moving from bottom to top influence the elements in the periodic table?

Increases electronegativity Signup and view all the answers

What does resilience refer to in materials?

The ability to absorb energy when deformed elastically and recover it Signup and view all the answers

How is engineering stress calculated?

Applied load divided by original cross-sectional area Signup and view all the answers

What is true stress in materials based on?

Instantaneous applied load divided by instantaneous cross-sectional area Signup and view all the answers

What is the defining feature of unsaturated molecules?

They have double or triple covalent bonds Signup and view all the answers

How do the intramolecular bonds in organic materials typically form?

Through covalent bonding Signup and view all the answers

What does true strain provide a more accurate measure of compared to engineering strain?

Change in length as material undergoes deformation Signup and view all the answers

What drives the hardening of inorganic cements like Portland cement?

Hydration Signup and view all the answers

What unique properties make oxide ceramics valuable?

Hardness, stiffness, and chemical resistance Signup and view all the answers

What is the primary mechanism of diffusion in ionic materials?

Vacancy diffusion Signup and view all the answers

Which technique is commonly used to measure the hardness of ceramic materials?

Knoop and Vickers hardness tests Signup and view all the answers

Why are bioceramics commonly used in biomedical applications?

Chemical inertness, hardness, and wear resistance Signup and view all the answers

What distinguishes diamond from graphite in terms of physical and chemical properties?

Diamond is a good conductor of electricity while graphite is not Signup and view all the answers

What is the main difference between the Bohr atomic model and the wave-mechanical model?

Bohr model describes electrons revolving in discrete orbitals, while the wave-mechanical model describes electrons as probability distributions. Signup and view all the answers

How does Schrödinger's atomic model differ from the Bohr atomic model?

Schrödinger's model considers electron position as a probability distribution, while the Bohr model assumes fixed electron positions. Signup and view all the answers

What is the significance of the Pauli exclusion principle in quantum mechanics?

It determines the number of electrons that can occupy each electron state and their spins. Signup and view all the answers

Which subshell can hold a maximum of 10 electrons according to quantum mechanics?

d Signup and view all the answers

What are valence electrons in an atom?

Electrons occupying the outermost shell Signup and view all the answers

In quantum mechanics, how is electron position described in Schrödinger's atomic model?

As a probability distribution or electron cloud Signup and view all the answers