Unit 7: Particulate Model of Matter Flashcards
Describe the arrangement and movement of the particles of solids.
The particles of a solid are closely packed and in an orderly arrangement. The particles vibrate about their fixed positions and there are very strong attractive forces between particles.
Describe the arrangement and movement of the particles of liquids.
The particles of a liquid are less closely packed than in a solid and are disorderly. The particles move freely throughout the liquid by sliding over one another. Strong attractive forces exist between the particles.
Describe the arrangement and movement of the particles of gases.
The particles of a gas are very far apart from each other in a disorderly arrangement. The particles move about rapidly in random directions and very weak forces of attraction exist between them.
What is melting?
Melting is the process in which a substance changes in state from solid to liquid at melting point.
What is freezing?
Freezing is the process in which a substance changes in state from liquid to solid at freezing point.
What is boiling?
Boiling is the process in which a substance changes state from liquid to gas at boiling point.
What is condensation?
Condensation is the process in which a substance changes state from gas to liquid at condensation point.
Describe melting using the particulate model of matter.
Particles of a solid gain kinetic energy and vibrate faster about their fixed positions. The energy gained by the particles is used to overcome the forces of attraction between them. They begin to break away from their orderly positions to become disorderly, sliding over each other.
Describe boiling using the particulate model of matter.
The particles of liquid are disorderly and slide faster over each other as they gain kinetic energy. This energy gained by the particles is used to overcome the forces of attraction between them and they move further apart, moving rapidly in random directions.
What are the differences between boiling and evaporation?
Boiling occurs throughout the liquid whereas evaporation takes place at the surface of the liquid. Boiling occurs at the boiling point whereas evaporation can occur at any temperature. Boiling occurs rapidly whereas evaporation occurs slowly.
What is diffusion?
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration.
How does temperature affect diffusion?
The higher the temperature, the higher the rate of diffusion. Particles gain more kinetic energy as the temperature increases. Thus, they can move faster, increasing the rate of diffusion.
How does the relative molecular mass of a gas affect diffusion?
Gases with lower relative molecular masses diffuse faster.
