8/27/10

Post date: Aug 27, 2010 7:58:40 PM

• • Questions on elements, compounds, and mixtures?

• Quiz #2

• Notes - Physical properties of matter

  • • Characteristics that can be observed without changing the identity of the substance

    • Help identify a substance

    • Can be observed or measured

      • Color

      • Melting point - temperature at which a substance will melt or freeze

      • Boiling point - temperature at which a substance will evaporate or condense

      • Strength - resistance to breaking

      • Hardness - resistance to bending or flexing

      • Magnetism - ability to be attracted to a magnet

      • Conductivity - ability to conduct electricity

      • Density - ratio of mass to volume of a substance

    • Help determine uses for a substance

• Notes - Density

  • • Is mass / volume

    • Is a physical property

    • Is constant for a given substance

    • Can be used to identify a material

    • Is DIFFERENT FROM WEIGHT!!!!!

      • People use "light" and "heavy" for weight and for density

      • Many would say a brick sinks in water because it is "heavy" -- actually, it is because the brick is more dense than water. A boat, which is much "heavier" than a brick, will float in water because it is less dense than water.

• Density Lab (due 9/1)