Lecture Notes: States of Matter and Density

Overview

• Learning Objectives
  • Draw diagrams to model particle arrangement in solids, liquids, and gases.
  • Calculate the density of materials.
  • Explain differences in density between different states of matter.

States of Matter

• Common States
  • Solids
  • Liquids
  • Gases

Particle Arrangement

• Solids

  • Particles are very close together.
  • Arranged in a regular pattern.
  • Particles vibrate but do not move from place to place.

• Liquids

  • Particles are close together but not arranged in a regular pattern.
  • Particles can move around each other.

• Gases

  • Particles are very far apart.
  • Not arranged in any pattern.
  • Particles move very rapidly.

Density

• Definition

  • Density indicates the mass for a given volume.
  • Measured in kilograms per meter cubed (kg/m³).

• Calculation

  • Formula: ( \text{Density} = \frac{\text{Mass (kg)}}{\text{Volume (m³)}} )
  • Important to memorize the formula as it is not provided in exams.

• Example Calculation

  • Given:
    • Mass = 150 kg
    • Volume = 0.3 m³
  • Calculate:
    • Density = 150 kg / 0.3 m³ = 500 kg/m³

Density in Different States

• Solids

  • Generally have high density due to closely packed particles.
  • High mass for their volume.

• Liquids

  • Also typically have high density because particles are close together.
  • High mass for their volume.

• Gases

  • Low density because particles are far apart.
  • Small mass for their volume.

• Exceptions

  • Polystyrene is a solid with low density due to its open structure filled with air spaces.

Additional Resources

• Vision workbook available for practice questions on density.