1. Hypothesis
    • An temporary explanation of the facts
    • observed. It can be tested.
  2. Law
    • It is a statement of a relationship between
    • phenomena. It states what
    • happens.
  3. Theory
    • A theory attempts an explanation of why something happens.
    • Theories evolve with time to explain new facts as they are discovered.
  4. Experiments
    • Systematic observations or measurements
    • carried (preferably) under controlled conditions to test the validity of a
    • hypothesis.
  5. Qualitative data
    • General observations, that may depend heavily
    • on the observer.
  6. Quantitative data
    • Measurable data, that in general depends less
    • of the observer and more of the instrumentation.
  7. Matter
    • What forms the material universe, occupies
    • space and has mass.
  8. Substance
    • Has a definite and constant composition. Has
    • physical and chemical properties.
  9. Mixture
    • Combination of substances where the
    • components retain their properties.
  10. Homogeneous mixture
    • Composition and properties of the mixture is
    • the same throughout the sample
  11. Heterogeneous mixture
    The composition is not uniform.
  12. Element
    • This substance cannot be separated into
    • simpler substances by chemical methods.
  13. Compounds
    • Made of atoms of elements bound together in a
    • fixed proportion.
  14. Transition from solid to liquid is given by
    the melting point.
  15. Transition from liquid to gas
  16. Direct transition from solid to gas is
    possible under certain conditions.
  17. Physical means
    • can be used to
    • separate a mixture into its pure components.
  18. chemical change
    • alters the
    • composition or identity of the substance(s) involved.
  19. Extensive Properties
    • •Depend on the amount of sample under
    • consideration
  20. Intensive Properties
    •Do not depend on the amount of sample
  21. Who first postulated the Atomic Theory?
  22. Who gave a precise definition of atom, element and compound?
    John Dalton
  23. Elements
    are composed of extremely small particles
  24. Compounds
    • composed of atoms of
    • more than one element
  25. Chemical reactions
    involve the rearrangement of atoms.
  26. cathode ray tube
    • used to observe
    • radiation in a laboratory setting.
  27. A high vacuum, a high
    voltage difference between two plates
    • cathode
    • and the anode
  28. cathode
    • the source of the
    • radiation
  29. Who measured the
    charge-to-mass ratio of the electron
    J. J. Thomson
  30. Who measured the
    charge of the electron
    R. A. Millikan
  31. How was the mass of
    the electron determined
    • A combination of Thomson’s and Millikan’s results
    • allowed to do that.
  32. Alpha
    • rays are positively
    • charged, massive.
  33. Beta
    • rays are electrons,
    • similar behavior as the radiation from the cathode ray tube experiment.
  34. Gamma
    • rays are not charged,
    • but very energetic.
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