Thursday, September 20, 2012

Describing Matter


In lab we make both qualitative and quantitative measurements.  We can further describe matter in terms of extensive and intensive properties.  Extensive properties are quantity specific, such as mass and volume. The mass of a sample of water depends on how much water you have in a sample. Intensive properties are dependent only on the type of matter, not the quantity.  The density of water is 1.0 g/mL whether you have a drop or a swimming pool full.

We can further divide observations into physical and chemical properties.  Physical properties describe matter without changing its composition.  Chemical properties describe how matter interacts or changes with other matter.

Physical Properties                                Chemical Properties
Color                                                                Rusting
Odor                                                                 Burning
Density                                                            Tarnishing
Boiling Point
Malleability

The state of matter, and its boiling and melting points are all physical properties.  The state of matter is determined by the arrangement of its particles.



The change of state of a substance is a physical change.
                                    Boiling                                                Evaporating
                                    Melting                                               Condensing
                                    Freezing                                              Sublimation
                                    Solidifying

If the identity of a substance is changed, or a new substance is formed, it is a chemical change.

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