Understanding Phases of Matter: Solids, Liquids, and Gases
This guide provides an overview of the three primary phases of matter: solids, liquids, and gases. It explains their characteristics, including volume and shape, molecular behavior, and the impact of heat on phase transitions. The concepts of diffusion, evaporation, and condensation are explored, along with the physical and chemical properties that distinguish different substances. Key properties such as density, melting points, and boiling points are discussed, along with the differences between extensive and intensive properties, illustrating the transformation of matter in various states.
Understanding Phases of Matter: Solids, Liquids, and Gases
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Presentation Transcript
Changes in Matter ISCI 2002 Chapter 11
Phases of Matter • Solid (s) ------ Liquid (l) --------- Gas (g) • Phases: ‘physical state’ • Solids • Definite volume and shape • Liquids • Definite volume, but form determined by container it is in • Gases • No definite volume or shape
Submicroscopic Level • Solids • Strong attraction between molecules- fixed position (vibrate) • Heat breaks fixed arrangement • Liquids • Molecules ‘flow’ • Gases • Heat causes attractions between individual molecules to be broken • Move in random manner • Bump into the container – ‘pressure’
Diffusion • Gasmolecules continue to move and bump into each other • Move from higherconcentration areas to lowerareasofconcentration • Occurs in: • Gases, liquids • Diffusion Animation
Phase Changes • Animation
Process of Evaporation • Molecules are heated below the surface, gain kinetic energy and bump into molecules at the surface • Surfacemolecules are released (attraction to other molecules broken) • Why is this a coolingprocess? • The slower moving molecules left behind (lower temperature) cools the air or body (perspiration)
Condensation • This is a warming process • Why? • Gasparticlescool and reach the surface. Kinetic energy absorbed by surface molecules. Molecules form attractions • This increases temperature
Chemical and Physical Properties • PhysicalProperties • Appearance – hard or soft; dull or shiny; color • Density; melting point and boiling point • ChemicalProperties-describes changes of composition the substance undergo’s during a chemical change • What is required to bring about the change • Temperature, heat, number of electrons, etc.
Chemical and Physical Properties • ExtensiveProperty • Depends on the ‘quantity’ of matter in a sample • Cannot be used to characterize a type of matter • Mass of water is 2.0 kg? Another sample may be 4.0 kg • Volume, mass • IntensiveProperty (distinguishes one substance from another) • Property shared by all examples of a specific type of matter • Density (m/v); color; melting point; solubility; acidic or alkaline • The density of water is 1.0 g/cm3
Physical and Chemical Properties • Physicalchange: a change in the physical properties of a substance. • Chemicalchange: the transformation of one or more substances into others.
