CHEMISTRY#2

Cards (14)

  • Matter: anything that has mass or takes up space.
  • Pure Substances: Matter that always has the same composition
    ex. table salt, sugar, sulfur,
  • fixed, uniform composition: every sample of a given substance has the same properties
    2 categories
    -elements
    ex. H, O, Si, C
    -compounds   
    ex. NaCl, KBr
  • Elements: - a substance that can not be broken down into simpler substances
    -119 elements
    -88 are found naturally,about 90%
    -not equally common
    -others are made in laboratories
  • Elements Cont:
    -majority of the elements are not found in abundance
    -some are exceedingly rare
    -only a dozen or so make up everyday things
    primarily: carbon, hydrogen, oxygen, nitrogen 
  • Compounds:  
    • a substance made of atoms of more than one element bound together
    • unique and different from the elements it contains
    • ex. Water: (H2O) liquid, clear, non toxic
  • Classifying Matter Cont.
    • Mixtures- combination of more than one pure substance
    ex. salsa, air, salad, pepper.
    • Two types of mixtures
    heterogeneous and homogenous
  • Heterogeneous
    -not uniform in composition
    -different components can be seen as individual substances
    ex: Oj: juice & water, pulp
  • Suspension(Heterogeneous)
    -mixtures that separates into layers over time
    -suspended particles settle out of solution or are trapped by filter
    -larger particles can scatter light: will be cloudy
    ex. O.J., sand/water, muddy water
  • Homogenous
    -substances are so evenly distributed that it is difficult to distinguish one substance from another
    -appears to contain only one substance
    ex. stainless steel: iron, nickel, chromium
  • Solutions(Homogenous)
    -mixtures that forms when substances dissolve and form a homogenous solution
    -particles are too small to settle, scatter light, or be trapped
    ex. salt water, windshield wiper fluid
  • Colloids(Heterogeneous)
    -mixtures that contain some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension.
  • Colloids (Heterogeneous) do not separate into layers
    ex. homogenized milk vs. cow’s milk, fog