CHEM 001 Class 4Class NotesJanuary 23, 2008C. Cecil Cuppett, Ph.D.Chapter 2:1.A physical propertyof a substance involves only the substance itself. In a physical property change, no chemical change occurs. Pure water remains water whether it is solid, liquid, or gas. Density, melting point, color, and hardness are some physical properties.2.Physical changes may occur such asfreezing(melting), boiling(condensation), or sublimation (deposition).3.Chemical changeis the changing of one substance into another substance. (Burning paper, rusting iron)4.Dissolvinga substance implies a second substance (solvent) is necessary to help with the dissolution. 5.Meltingimplies just one pure substance becomes hot enough to turn from a solid into a liquid.6.Evaporation is the process of a molecule escaping the liquid phase and going to a gas phase. Our noses are good vapor detectors. Liquids that evaporate easily are said to be volatileand create a high vapor pressure. (gasoline, perfume, acetone, and turpentine)7.Watching water boil allows you to see the liquid change to gas in a dramatic way. When water boils, the
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