Constantly flying around, bumping into each other and the container •A lot of empty space between the particle - compressible Indefinite volume and indefinite shape Matter classified by physical form: Matter classified by physical form: Matter classified by physical form:
Matter classified by chemical composition: Periodic Table (pure elements) Classify each diagram as a pure substance or a mixture; then element/compound and homogeneous/heterogeneous.
Question 3: Which of the following is a pure substance? A. Coffee B. Soda C. Ice D. Seawater E. Gasoline Question 4: Classify each substance as a pure substance or a mixture; then element/compound and homogeneous/heterogeneous. A. Wine B.Beef stew C. Iron D.Carbon dioxide Separating Mixtures
Physical Separation Methods •Decanting - separating a heterogeneous mixture with particle size, e.g., sand and water, iron filings and water •Filtration - separating a heterogeneous mixture using a filter Physical Separation Methods Distillation – separating homogeneous mixtures with different volatilities Examples: •Oil refining •Seawater desalination •Alcohol production Physical Changes Changes in Matter Chemical Changes Changes that alter state or appearance (not composition) Changes that alter chemical composition
Physical Changes •When water boils, it changes into a gas •Its chemical composition is not changed •Water molecules are the same in the gas phase as in the liquid phase Chemical Changes •The rusting of iron is a chemical change •The iron atoms combine with oxygen in the air to form a different chemical substance (iron oxide) Properties of Matter Physical propertiesare the characteristics of matter that can be changed without changing its composition – characteristics that are directly observable – Examples: •state, size, mass, volume, color, odor, melting point, boiling point, density, solubilityChemical propertiesare the characteristics that determine how the composition of matter changes as a result of contact with other matter or the influence of energy – characteristics that describe the behavior of matter – Examples: •Flammability, corrosiveness, bleaching power explosiveness
Physical Changes versus Chemical Changes Physical Changes versus Chemical Changes Physical Changes versus Chemical Changes