Particle Theory and the Kinetic Molecular Theory Pg 418-423 Homework: p. 422#1,2,3a p. 422 #1,3,4
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
Solids and Liquids Gases 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 Solids: vibrational (vibrate around a fixed point) Liquids: vibrational and rotational (particles rotate and change positions)
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
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) Electrostatic: oppositely charged particles attract each other Polar: particles are not charged but attractions can still form Intermolecular: between neutral molecules or molecules and ions
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:
Kinetic Molecular Theory of Gases State the Kinetic Molecular Theory of Gases The KMT describes a hypothetical gas called an ideal gas Ideal Gas: Particles take up hardly any space Particles do not attract one another Allows us to make generalizations about real gases