Kinetic Molecular Theory/Heat Transfer Solids & Liquids

Kinetic Molecular Theory of Liquids Particles of a liquid are in constant motion. Particles are closer together and have a lower kinetic energy than gas particles. –Therefore attractive forces in liquids are more effective than those between particles in a gas

Particles are not bound together in fixed positions; therefore they are constantly moving. Liquids are fluid –Liquids are more ordered than gases because of stronger intermolecular forces and lower mobility

Liquid Characteristics Relatively High Density- most substances are 1000x denser as liquids than as gases. This is due to the close arrangement of liquid particles

Relative Incompressibility- Liquid particles compress very little due to the fact that the particles are closely packed together.

Ability to Diffuse- Liquids will diffuse in any other liquid which it can dissolve. –This is because of the random constant motion of the particles –Diffusion of liquids is slower than gases because liquid particles are closer together –Attractive forces also slow movement –The higher the temperature the faster the diffusion (b/c of increased average KE)

Surface Tension A force that tends to pull adjacent parts of a liquids surface together, decreasing the surface area to the smallest possible size –Results from attractive forces between particles

Kinetic Molecular Theory of Solids Due to the particles being so closely packed, intermolecular forces are much stronger These forces hold the particles in a fixed position, with vibrational movement only Solid particles are highly ordered

2 Types of Solids 1. Crystalline Solids- consist of crystals which are arranged in an orderly, geometric, repeating pattern 2. Amorphous Solids-particle are arranged randomly (glass and plastic).

Solid Characteristics Definite Shape and Volume Definite Melting Point –Amorphous Solids do not have a definite melting point High Density –Most substances are most dense in the solid state because particles are so closely packed High Incompressibility Low Rate of Diffusion –Millions of times slower than liquids

Heat Transfer Transfer of heat is normally from a high temperature object to a lower temperature object Heat transfers…cold does not transfer (cold is the absence of heat)

Conduction-Solids The result of collisions between molecules When one end of an object is heated, the molecules vibrate faster and the energy is transferred to the neighboring molecules

Convection-Liquids & Gases Heat transfer by the movement of currents within a fluid (both liquids and gases are fluid!). When a liquid or gas is heated the particles begin to move faster and spread apart. Heated particles begin to flow which transfers heat from one part of a fluid to another