Presentation on theme: "Properties and Changes. Physical Properties Can be observed or measured. Density Color Odor Taste Hardness Melting point Boiling point Extensive or Intensive?"— Presentation transcript:
Signs of a Chemical Change/Reaction Color change Odor Bubbles / production of a new gas Precipitate / formation of a new solid from combining two solutions Heat (energy) being absorbed or given off / becoming cold or hot Irreversible / reactants -> products
Matter: Mixture or Substance? Mixture: Homogeneous or Heterogeneous? Homogeneous = uniform composition (solutions, alloys) Can be physically separated into multiple substances Substance: Element or Compound? Substance = definite composition Element = found on the Periodic Table Compound = can be chemically separated into Elements
Law of Conservation of Mass (Energy) Mass (Energy) is neither created nor destroyed in any physical change or chemical reaction; it is conserved. Law of Definite Proportions Regardless of amount, a specific compound is always composed of the same elements in the same proportion by mass. Law of Multiple Proportions In forming compounds, different masses of one element combine with the same masses of another element in a ratio of small whole numbers.