Question 1

Which of the following best explains why the Boeing 787 Dreamliner uses composite materials instead of traditional metals?

Accepted Answer

Composite materials provide a high strength-to-weight ratio, making the airplane lighter and more fuel-efficient.

Question 2

Which type of solid is sodium chloride (NaCl) and what is its primary force of attraction?

Accepted Answer

Ionic crystal; electrostatic attraction between ions

Question 3

Why do metallic crystals, such as aluminum, conduct electricity well in the solid state?

Accepted Answer

They contain mobile valence electrons that move freely throughout the crystal.

Question 4

Which property is NOT characteristic of molecular crystals such as ice?

Accepted Answer

Electrical conductivity in solution

Question 5

Diamond is an example of which type of solid, and what accounts for its extreme hardness?

Accepted Answer

Covalent network crystal; interlocking network of covalent bonds

Question 6

Which of the following best describes the bonding in metallic crystals according to the electron sea theory?

Accepted Answer

Positive nuclei are held together by a sea of mobile electrons.

Question 7

A solid that does not conduct electricity as a solid but does when dissolved in water is most likely:

Accepted Answer

An ionic crystal

Question 8

Which of the following solids would you expect to have the lowest melting point?

Accepted Answer

Ice

Question 9

Why does graphite, unlike diamond, conduct electricity?

Accepted Answer

Graphite contains delocalized electrons that can move between layers.

Question 10

Which process is used to modify the electrical properties of semiconductors such as silicon?

Accepted Answer

Doping with small amounts of other elements

Question 11

A sample of solid carbon dioxide (dry ice) and a sample of ice (solid water) are both molecular crystals. Which property do they share?

Accepted Answer

Both have low melting points due to weak intermolecular forces.

Question 12

Which of the following is a real-world application of buckyballs (buckminsterfullerene)?

Accepted Answer

Used in photovoltaic cells and drug delivery systems

Question 13

Which of the following best distinguishes an ionic crystal from a molecular crystal in a laboratory setting?

Accepted Answer

Test electrical conductivity in solution; ionic crystals conduct, molecular crystals do not.

Question 14

Which of the following statements about glass is correct?

Accepted Answer

Glass is an amorphous solid with a disordered structure.

Question 15

Which type of solid is most likely to be malleable and have a shiny appearance?

Accepted Answer

Metallic crystal

Question 16

A scientist is testing a new material that is extremely hard, has a very high melting point, and does not conduct electricity. Which type of solid is this most likely to be?

Accepted Answer

Covalent network crystal

Question 17

Which of the following best explains why semiconductors are essential in modern electronics?

Accepted Answer

Their conductivity can be precisely controlled by doping and temperature changes.

Question 18

Which of the following is a property of an n-type semiconductor?

Accepted Answer

It is doped with an element that has more valence electrons than the host crystal.

Question 19

Which of the following best describes the difference between quartz and glass?

Accepted Answer

Quartz is crystalline with a regular structure, while glass is amorphous with a disordered structure.

Question 20

Which of the following solids would be expected to have the greatest electrical conductivity in the solid state?

Accepted Answer

Aluminum

Lesson 4.8: The Structure and Properties of Solids

Guida di studio - Domande di pratica

Study guide - Flashcard