Liquids Chapter 12.1 Objectives Describe the motion of particles in liquids and the properties of liquids according to the kinetic-molecular theory. Discuss the process by which liquids can change into a gas. Define vaporization. Discuss the process by which liquids can change into a solid. Define freezing.
Liquids Examples: Oceans, lakes, rivers Hard to believe – liquids are the least common state in the universe Why? Narrow temperature range they can exist in!
Properties of Liquids and Kinetic-Molecular Theory Definite volume, take shape of container According to Kinetic-Molecular Theory Liquid’s particles are: In constant random motion Closer together than gases, there are attractive forces More ordered than gases, so particles are held together, but do have mobility. Fluid: substance that can flow and therefore take the shape of its container
Relatively High Density Thousands of times denser than gases Slightly less dense than solids Due to the close arrangement of liquid particles
Relative Incompressibility Less compressible because particles are packed together Ability to Diffuse
Liquids will diffuse in other liquids it can dissolve in.
Surface Tension Force that tends to pull adjacent parts of a liquid’s surface together, thereby decreasing surface area to the smallest possible size. Water has high surface tension Hydrogen bonding are strong intermolecular forces Capillary Action Attraction of the surface of a liquid to the surface of a solid
Evaporation and Boiling Vaporization: Process by which a liquid or solid changes to a gas Evaporation: Process by which particles escape from the surface of a non-boiling liquid and enter the gas state. Boiling: Change in liquid to bubbles of vapor that appear throughout the liquid.
Formation of Solids When liquid is cooled, average kinetic energy decreases Particles slow down Attractive forces pull into an orderly arrangement Freezing (solidification): Physical change of a liquid to a solid by removal of heat.