7-1 Intro to Phases of Matter

Which of the following best represents a particle diagram of a solid?

• Particles are in a fixed position, closely packed in a regular pattern.

• Particles are far apart and moving at high speeds.

• Particles are close together but move freely around each other.

• Particles are in a random pattern and not touching.

Answer explanation

A) correctly describes a solid's particle arrangement, where particles are tightly packed in fixed positions, forming a regular pattern. This contrasts with the other options, which depict liquids or gases.

What happens to the energy of particles as a liquid is heated?

• The energy decreases, causing particles to move more slowly.

• The energy remains constant, but the particles move in a fixed position.

• The energy increases, causing particles to move more rapidly.

• The energy is used to create new particles

Answer explanation

As a liquid is heated, the energy of its particles increases, leading to more rapid movement. This is why the correct answer is C, as higher temperatures result in greater kinetic energy of the particles.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which property is characteristic of solids?

• They have a definite shape and volume.

• They have an indefinite shape but a definite volume.

• They have an indefinite shape and volume.

• They have a definite shape but an indefinite volume.

Answer explanation

Solids are characterized by having a definite shape and volume, meaning they maintain their form and size regardless of the container they are in. Therefore, the correct answer is A) They have a definite shape and volume.

Intermolecular forces in liquids determine:

• The shape of the liquid.

• The boiling point of the liquid.

• The color of the liquid.

• The electrical conductivity of the liquid.

Answer explanation

Intermolecular forces significantly influence the boiling point of a liquid. Stronger forces result in higher boiling points, as more energy is needed to overcome these attractions, making option B the correct choice.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which of the following is not a typical property of gases?

• Gases fill their container.

• Gases have low density.

• Gases are compressible.

• Gases have a fixed shape.

Answer explanation

D) Gases have a fixed shape is incorrect because gases do not have a fixed shape; they take the shape of their container. In contrast, gases fill their container, have low density, and are compressible.

Which phase change involves a solid becoming a gas without passing through the liquid state?

• Melting

• Freezing

• Sublimation

• Condensation

Answer explanation

The phase change where a solid turns directly into a gas is called sublimation. This process skips the liquid state entirely, unlike melting (solid to liquid) and condensation (gas to liquid). Thus, the correct answer is C) Sublimation.

In a phase diagram, the line between the solid and liquid states represents:

• The points at which solid and liquid are in equilibrium.

• The temperature at which all solids become liquids.

• The pressure at which all liquids become solids.

• The density difference between solid and liquid states.

Answer explanation

The line between solid and liquid states in a phase diagram indicates the equilibrium points where both phases coexist. Thus, the correct answer is A) The points at which solid and liquid are in equilibrium.

Tags

NGSS.MS-PS1-4

Which of the following best describes the particles in a gas?

• They are arranged in a geometric pattern with strong intermolecular forces.

• They are tightly packed together and vibrate in place.

• They are at a considerable distance from each other and move randomly.

• They slide over each other but are still closely packed.

Answer explanation

In a gas, particles are far apart and move randomly, which allows them to fill their container. This distinguishes them from solids and liquids, where particles are more closely packed and have limited movement.

Organize the phase changes into the correct categories:

Groups:

(a) Exothermic

,

(b) Endothermic

• Melting

• Deposition

• Vaporization

• Sublimation

• Condensation

• Freezing

Tags

NGSS.MS-PS1-4

Organize these options into the right categories

Groups:

(a) Solid

,

(b) Liquid

,

(c) Gas

• highly mobile particles

• highest entropy

• definite shape

• can flow

• fixed volume

• high density

• compressible

• lowest potential energy

• particles less tightly packed than solids

• high attraction between particles

• takes the shape of its container

• high diffusion rate

• particles far apart

• indefinite shape

• incompressible under normal conditions

• particles closely packed

• highest kinetic energy

• not compressible

• fills the container

• low density

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4