An Introduction to Chemistry（介绍化学）.pdf

Chapter 2 The Structure of Matter and the Chemical Elements An Introduction to Chemistry By Mark Bishop Chapter Map Chemistry The science that deals with the structure and behavior of matter Scientific Models •  A model is a simplified approximation of reality. •  Scientific models are simplified but useful representations of something real. Kinetic Molecular Theory •  All matter is composed of tiny particles. •  The particles are in constant motion. •  Increased temperature reflects increased motion of particles. •  Solids, liquids and gases differ in the freedom of motion of their particles and in how strongly the particles attract each other. Solid •  Constant shape and volume •  The particles are constantly moving, colliding with other particles, and changing their direction and velocity. •  Each particle is trapped in a small cage whose walls are formed by other particles that are strongly attracted to each other. The Nature of Solids Liquid •  Constant volume but variable shape •  The particles are moving fast enough to break the attractions between particles that form the walls of the cage that surround particles in the solid form. •  Thus each particle in a liquid is constantly moving from one part of the liquid to another. Liquids Evaporation Gas •  Variable shape and volume •  Large average distances between particles •  Little attra