Particle Theory and the Kinetic Molecular Theory

1
Particle Theory and the Kinetic Molecular Theory

• Pg 418-423
• Homework
• p. 4221,2,3a
• p. 422 1,3,4

2
Particle Theory of Matter

• Matter is made up of tiny particles (atoms, ions,
  molecules) that are in constant motion
• Particles have spaces between them
• Draw particle diagrams to describe and compare
  the relative spacing of particles in solids,
  liquids and gasses.

Solid Liquid Gas
3
Solids and Liquids

• These particles cannot move independently
• Incompressible
• Vibrational motion (solids)
• Vibrational, rotational, and translational motion
  (liquids)

Gases

• Are able to move independently
• Motion is fast
• Compressible
• Translational motion is most significant

4
Forces Between Particles

• Particles are held together by strong attractive
  forces
• Describe and compare the relative attractive
  forces between particles in solids, liquids and
  gasses
• The strength of attractive forces between
  particles depends on
• Type of force
• Temperature

5
Types of Forces

• Attractions Between Charged Particles
• Electrostatic attraction e.g. ionic bonding
• Very strong
• Attractions Between Polar Molecules
• Intermolecular forces
• Dipole-dipole
• Not as strong
• Attractions Between Non-Polar Molecules
• London forces (temporary dipoles)
• Weak and temporary
• Depend on size (forces add up)

6
Temperature

• Related to kinetic energy
• When heated
• Particles move faster and have more collisions
• Higher kinetic energy (helps to overcome
  attractive forces)
• Take up more space making the object expand
• When cooled

7
Kinetic Molecular Theory of Gases

• State the Kinetic Molecular Theory of Gases
• The KMT describes a hypothetical gas called an
  ideal gas
• Ideal Gas